Wikipedia:Manual of Style/Linking

Linking through hyperlinks is an important feature of Wikipedia. Internal links bind the project together into an interconnected whole. Interwikimedia links bind the project to sister projects such as Wikisource, Wiktionary and Wikipedia in other languages, and external links bind Wikipedia to the World Wide Web.

Appropriate links provide instant pathways to locations within and outside the project that can increase readers' understanding of the topic at hand. Whenever writing or editing an article, consider not only what to put in the article, but what links to include to help the reader find related information, and also which other pages should have links the article. Avoid both underlinking and overlinking, as described below.

This page provides guidelines as to when links should and should not be used, and how to format links. For information about the syntax used to create links, see Help:Link. For links on disambiguation pages, see Manual of Style/Disambiguation pages.

Principles
Wikipedia is based on hypertext, and aims to "build the web" to enable readers to access relevant information on other Wikipedia pages easily. The page from which the hyperlink is activated is called the anchor; the page the link points to is called the target.

In adding or removing links, consider an article's place in the knowledge tree. Internal links can add to the cohesion and utility of Wikipedia, allowing readers to deepen their understanding of a topic by conveniently accessing other articles. Ask yourself, "How likely is it that the reader will also want to read that other article?" Consider including links where readers might want to use them; for example, in article leads, at the openings of new sections, in the cells of tables, and in file captions. But as a rule of thumb, link only the first occurrence of a term in the text of the article.

General points on linking style

 * As explained in more detail at, linking can be direct ( , which results in Riverside, California), or piped ( , which results in Riverside in the text, but still links to the article "Riverside, California"—although the pipe trick is an easier way to create this particular link).
 * Section headings should not themselves contain links; instead, a main article or see also template should be placed immediately after the heading.
 * Links should not be placed in the boldface reiteration of the title in the opening sentence of a lead.
 * Be conservative when linking within quotations; link only to targets that correspond to the meaning clearly intended by the quote's author. Where possible, link from text outside of the quotation instead – either before it or soon after.
 * When possible, do not place links next to each other, to avoid appearing like a single link, as in chess tournament . Instead, consider rephrasing the sentence (tournament of chess), omitting one of the links (chess tournament), or using a single, more specific link as in chess tournament.
 * For geographic places specified with the name of the larger territorial unit following a comma, generally do not link the larger unit.
 * For example, avoid
 * Sydney, Australia
 * or
 * Buffalo, New York, United States
 * Instead, use
 * ✅Sydney, Australia
 * or
 * ✅Buffalo, New York, United States


 * Linked text should avoid leading and trailing spaces. Punctuation, including spaces, should be external to the linked items.
 * Articles on technical subjects might demand a higher density of links than general-interest articles, because they are likely to contain more technical terms that general dictionaries are unlikely to explain in context.
 * Beware of linking to an article without first confirming that the target article covers the appropriate topic. For example, an article mentioning the physics unit "barn" should link to barn (unit), not barn.
 * In articles, do not link to pages outside the article namespace, except in articles about Wikipedia itself (and even in that case with care – see Manual of Style/Self-references to avoid).
 * Do not unnecessarily make a reader chase links: if a highly technical term can be simply explained with very few words, do so.
 * Use a link when appropriate, but as far as possible do not force a reader to use that link to understand the sentence. The text needs to make sense to readers who cannot follow links. Users may print articles or read offline, and Wikipedia content may be encountered in republished form, often without links.
 * Refrain from implementing colored links that may impede user ability to distinguish links from regular text, or color links for purely aesthetic reasons.

What generally should be linked
An article is said to be underlinked if unlinked words are needed to aid understanding of the article. In general, links should be created for:
 * Relevant connections to the subject of another article that will help readers understand the article more fully (see the example below). This can include people, events, and topics that already have an article or that clearly deserve one, as long as the link is relevant to the article in question.
 * Articles with relevant information, for example: "see Fourier series for relevant background"
 * Articles explaining words of technical terms, jargon or slang expressions or phrases—but you could also give a concise definition instead of or in addition to a link. If there is no appropriate Wikipedia article, an interwikimedia link to Wiktionary could be used.
 * Proper names that are likely to be unfamiliar to readers

If you feel that a link is relevant to the topic of the article but does not belong in the body of an article, consider moving it to a "See also" section.

Links may be created to potential articles that do not yet exist (see ). If an article exists on a foreign-language Wikipedia but not yet in English, consider a red link that also links to the foreign-language article (see ).

What generally should not be linked
An article is said to be overlinked if it contains an excessive number of links, making it difficult to identify those likely to aid a reader's understanding. A good question to ask yourself is whether reading the article you're about to link to would help someone understand the article you are linking from. Unless a term is particularly relevant to the context in the article, words and terms understood by most readers in context are usually not linked. Be conscious of your own demographic biases when determining whether certain terms have this level of recognizability – what is well known in your age group, line of work, or country may be less so for others. Examples include: In addition, examples of the following categories should generally not be linked:
 * Everyday words (e.g., education, violence, aircraft, river, animation)
 * Common occupations (e.g., accountant, politician, actor)
 * Common units of measurement, often those relating to time, temperature, length, area, or volume. If both non-metric and metric equivalents are given, as in 5 cm, usually neither unit needs to be linked, because almost all readers will understand at least one of the units.
 * Dates
 * Disambiguation pages should not be linked from articles unless the link is purposeful, such as in a hatnote. Instead, use a piped link to the appropriate article. For example, use Moana for the Disney character, which appears as Moana and leads to the intended pageinstead of Moana, which appears identical but leads to a disambiguation page.
 * Countries (e.g., Brazil/Brazilian, Canada/Canadian, China/Chinese)
 * Geographic features (e.g., the Himalayas, Pacific Ocean, South America)
 * Settlements or municipalities (e.g., New Delhi; New York City, or just New York if the city context is already clear; London, if the context rules out London, Ontario; Southeast Asia)
 * Languages (e.g., English, Arabic, Korean, Spanish)
 * Nationalities, ethnicities or identities (e.g., British, Japanese, Turkish, African American, Nigerian)
 * Religions (e.g., Christianity, Islam, Hinduism, Buddhism)

Links may be excessive even if they are informative. For example, because inline links present relatively small tap targets on touchscreen devices, placing several separate inline links close together within a section of text can make navigation more difficult for readers with limited dexterity or coordination. Balance readability, information, and accessibility when adding multiple links in one section of text.

Do not link to pages that redirect back to the page the link is on (unless the link is to a redirect with possibilities that links to an appropriate section of the current article).

The purpose of linking is to clarify and to provide reasonable navigation opportunities, not to emphasize a particular word. Do not link solely to draw attention to certain words or ideas, or as a mark of respect.

External links normally should not be placed in the body of an article (see External links).

Duplicate and repeat links
Link a term at most once per major section, at first occurrence. Common sense applies; do not re-link in other sections if not contextually important there. Other mentions may be linked if helpful, such as in infoboxes, tables, image captions, footnotes, and hatnotes.

Citations stand alone in their usage, so there is no problem with repeating the same link in many citations within an article; e.g..

In glossaries, which are primarily referred to for encyclopedic entries on specific terms rather than read from top to bottom like a regular article, it is usually desirable to repeat links (including to other terms in the glossary) that were not already linked in the same entry.

Duplicate linking in stand-alone and embedded lists is permissible if it significantly aids the reader. This is most often the case when the list is presenting information that could just as aptly be formatted in a table, and is expected to be parsed for particular bits of data, not read from top to bottom. If the list is normal article prose that happens to be formatted as a list, treat it as normal article prose.

Duplicate links in an article can be found using the duplinks-alt sidebar tool.

Lead section
Too many links can make the lead hard to read. In technical articles that use uncommon terms, a higher-than-usual link density in the lead section may be necessary. In such cases, try to provide an informal explanation in the lead, avoiding using too many technical terms until later in the article. (See Make technical articles understandable and Wikipedia is not a scientific journal.)

Most Featured Articles contain about 12 to 25 links in the lead, with an average of about 1.5 links per sentence, or one link for every 16 words.

An example article
For example, in the article on supply and demand:
 * Almost certainly link "microeconomics" and "general equilibrium theory", as these are technical terms that many readers are unlikely to understand at first sight.
 * Consider linking "price" and "goods" only if these common words have technical dimensions that are specifically relevant to the topic.
 * Do not link to the "United States", because that is an article on a very broad topic with no direct connection to supply and demand.
 * Definitely do not link "wheat", because it is a common term with no particular relationship to the article on supply and demand, beyond its arbitrary use as an example of traded goods in that article.
 * Make sure that the links are directed to the correct articles: in this example, you should link goods, not good, which goes to a page on the philosophical concept. Many common dictionary words are ambiguous terms in Wikipedia and linking to them is often unhelpful to readers; "Good" is a surname and the name of albums, companies, etc., and the article title Good (disambiguation) is used to index those.

Link clarity
The article linked to should correspond as closely as possible to the term showing as the link, given the context.

For example, a link to the article Requiem (Mozart) should be clear that it is Mozart's Requiem in particular, rather than requiems in general. The link target and the link label do not have to match exactly, but the link must be as intuitive as possible (see ).

Link specificity
Always link to the article on the most specific topic appropriate to the context from which you link: it will generally contain more focused information, as well as links to more general topics.

If there is no article about the most specific topic, do one of the following things:
 * Consider creating the article yourself.
 * If an article on the specific topic does not yet exist, create a redirect page to the article about a more general topic, as described in section . For example, if no article yet exists on the song "Sad Statue" from the album Mezmerize, create a new article called Sad Statue that is a redirect to the article Mezmerize.
 * If there is no article on a more general topic either, then create a red link, but first, read below.

When neither a redirect nor a red link appears appropriate, consider linking to a more general article instead.

For example, instead of Baroque hairstyles (an article which, as of 2023, had never been created), write ✅Baroque hairstyles (which will provide a link to the Baroque era), ✅Baroque hairstyles (which provides a link to the article on hairstyle), ✅Baroque hairstyles (which provides no link at all, and which may be preferable depending on context), or ✅hairstyles of the Baroque (which provides separate links to both topics); however, do not create Baroque hairstyles as two adjacent links because they may be misinterpreted as linking to a single article on that topic.

Section links
If an existing article has a section specifically about a topic, linking to that section takes the reader directly to the relevant information. Section-linking options are piped links, redirects, and the template, which also generates the § character.

Avoiding broken section links
A problem can arise if the title of the section is changed for any reason, since this action will break any incoming section links or excerpts. (If this occurs, incoming links will default to the top of the linked article.) The recommended way to prevent this breakage is to use a template specifying the section's prior name.

An alternative, supplementary method has been to add a hidden comment to the target section such as so that someone changing the title of that section can fix the incoming links. This method is weaker, since it puts the workload on the editor seeking to change the section title.

There are some bots aimed to fix broken anchors: cewbot,, and.

Redirects
Suppose you need to link poodle, and there is no such article yet. You might want to create a redirect from "poodle" to "dog" as follows: Link as usual:. When you save or preview this, you will see: She owned a poodle. Click on the red link, and you will be invited to create a new page for poodle; enter (perhaps), so that readers clicking on poodle will be taken, for now, to the dog article.

The redirect is better in a case like this than a direct link like, because when an actual poodle article is eventually created (replacing the redirect), readers clicking on poodle will be taken there automatically without anyone needing to review all the links to dog to see which ones should actually go to poodle.

To link to a redirect page without following the underlying redirect, use e.g.. Avoid linking redirects that are self links (WP:SELFRED).

Piped links
Though a wikilink defaults to displaying the title of the target article, it is possible to choose more specific or more appropriate display text for the intended context. This can be done with the use of the pipe character (|). For example, displays as Henry II. However, make sure that it is still clear what the link is about without having to follow the link. Think about what the reader may believe the text refers to. For example, when seeing the link, which displays as Archery, the reader will probably expect this link to go to a general article on archery, rather than Archery at the 2008 Summer Olympics specifically. An exception to this is when it is clear from the context that a link refers to a specific article; for instance, in Template:Events at the 2008 Summer Olympics all links go to articles about these particular games.

Style

 * Plurals and other derived names. displays as apples, and this is simpler and clearer than . Similarly:, , . Some characters will not work after the link; see Help:Link for more details.
 * Case sensitivity. Links are not sensitive to initial capitalization, so there is no need to use the pipe character where the case of the initial letter is the only difference between the link text and the target page. (Wikipedia article titles almost always begin with a capital, whereas the linked words in context often do not.) However, links are case-sensitive for all characters after the initial one.

Intuitiveness


Keep piped links as intuitive as possible. Per the principle of least astonishment, make sure that the reader knows what to expect when clicking on a link. You should plan your page structure and links so that everything appears reasonable and makes sense.

A link's visible label does not need to match the exact title of the article being linked, such as in Lorry or passed the ball. However, avoid "Easter egg" or "submarine" links, which are links that unexpectedly hide relevant information underneath the link's label. For example, do not write: Here readers would see the link displayed as particle physics, not the hidden reference to the page Parton (particle physics), unless they clicked on the link or hovered their mouse cursor over it. If a physical copy of the article were printed, the reference to the parton model would be lost.

Instead, refer to the separate article with an explicit see also X, or by rephrasing the sentence, as in:

More words into a link
Sometimes moving other words into the bluelinked text avoids surprise.

For example, in an article on the history of Texas: appears as:     In 1845, the Republic of Texas was annexed by the United States. which looks the same as a link to the generic topic of annexation would. However: appears as:     In 1845, the Republic of Texas was annexed by the United States. and is clear that the 1845 annexation of Texas is linked.

Names in names
Do not place a link to a name within another name. For example: The above applies regardless of whether linking to the full name creates a red link; for example, even if there is no article titled Lafayette Avenue (Brooklyn):

See also.

Piping and redirects
As per WP:NOTBROKEN and above, do not use a piped link where it is possible to use a redirected term that fits well within the scope of the text. For example, the page Papageno is a redirect to the article about Mozart's opera The Magic Flute. While editing some other article, you might want to link the term Papageno; here, you might be tempted to avoid the redirect by using a pipe within the link, as in. Instead, write simply and let the system handle the rest. This has two advantages: first, if an article is written later about the more specific subject (in this case, "Papageno"), fewer links will need to be changed to accommodate the new article; second, it indicates that the article is wanted. An exception to this rule is when linking to articles in Did you know (DYK) "hooks" on the Main Page, where piping links to prevent readers from seeing a redirect notice is preferable, and the hook will be live only for a short time.

Piped links and redirects to sections of articles
As explained above, links to sections can take the reader directly to relevant information.

Piped links.

Using a piped link to sections avoids the unsightly Article name#Section name in the display text.

The format for a piped link is. For example, to link to the "Culture" subsection of the article Oman, type which displays as culture of Oman. Then add a hidden comment to the target section such as  so that if another user edits the title of that section, they can fix the incoming links (or, in cases where a section has a large number of incoming links, use  on the anchor page).
 * (note that the section name is case-sensitive),

To link to a section within the same article, write:.

Redirects to sections which may become articles.

Many topics useful for linking may currently appear only as sections of other Wikipedia articles, but are potentially notable enough to become articles on their own. For example, the article Eastern Anyshire might have a small "History" section, but this does not prevent the article History of Eastern Anyshire being written eventually. Usually, a redirect page from such a sub-topic to a general topic will exist already; if not, they can be created when the occasion arises. It is bad practice to create links in article text using the format ; navigation then becomes difficult if the section is expanded into a new article. Instead, link using a redirect to the main topic; it costs little and makes improvements easier. Thus:
 * In a redirect page named " History of Topic ", use.
 * In another article, use.
 * Avoid:.

Links to foreign-language pages
See.

Links to Wikipedia's categories
Wikipedia has categories of articles like ; adding this to an article puts it into that category. You can link to a category by putting a colon in front.

For example links to Category:Phrases, and piping can be used: Phrases.

creates:

Red links
Overlinking in general is a style issue partly because of the undesirable effect upon readability. But if too many blue links is distracting (reducing the chance the article will be read), then a red link is even more so. The unassuming coloration of the text (probably black) is the most productive.

In prose, if it seems that the level of red linking is overlinking, remember that red links have been found to be a driving force that encourages contributions, and then use that fact to balance the perceived stylistic issues of "overlinking" the red links. (Legitimate red links are titles to unfulfilled coverage of topics that do not violate "What Wikipedia is not" policy.) Given a certain number of red links needed, if marking of them could be overlinking, then just  should be marked could be a style issue, and just  are priority is a helpful contribution.

In lists, overlinking red links can occur when every item on a list is a red link. If the list is uniform, where each item is obviously qualified for an article, a red link (or blue link) could indicate that. If the list is not uniform, the research effort to mark all possible red links is a risky investment: while red means "approved" status, "black" remains ambiguous, even though it meant "disapproved". Valid requests for the future creation of each title in a list, or in prose, may also be a risky investment when the number of red links could be perceived by other editors as overlinking, and then removed before the investment was fruitful. The removal of massive numbers of red links from an overlinked list is best handled by an editor skilled in the automation of text processing.

Red links can also be removed if they violate policy or the guideline for red links, but otherwise red links do not have an expiration date. If you remain convinced there is overlinking of red links, consider turning some of them blue. The methods to do so are by creating a simple stub, a redirect, or a disambiguation page. All of these require the certainty that the red link was legitimate in the first place, such as the conventions on article titles.

Colored links
In prose, refrain from implementing colored links, as these may impede user ability to distinguish links from regular text. See the guides to editing articles for accessibility at contrast and navbox colors.

Checking links as they are created
It's easy to create an erroneous link without realizing it. When adding a new link, it's a good idea to click on the "Show preview" button and then (from the preview) open the link in a new browser tab to check that it goes where you intend.

By following naming conventions, an internal link will be much more likely to lead to an existing article. When there is not yet an article about the subject, a good link will make it easier to create a correctly named article later.

Linking month-and-day or year
Month-and-day articles (e.g. February 24 and 10 July) and year articles (e.g. 1795, 1955, 2007) should not be linked unless the linked date or year has a significant connection to the subject of the linking article, beyond that of the date itself, so that the linking enhances the reader's understanding of the subject. For example: However, in intrinsically chronological articles (1789, January, and 1940s), links to specific month-and-day, month-and year, or year articles are not discouraged.
 * The date (or year) should not be linked in a sentence such as (from Sydney Opera House): "The Sydney Opera House was made a UNESCO World Heritage Site on 28 June 2007", because little if any content of either June 28 or 2007 pertains to either UNESCO, World Heritage Sites, or the Sydney Opera House.
 * The years of birth and death of architect Philip Johnson should not be linked, because little if any content of 1906 or 2005 enhance the reader's understanding of Johnson or his work.
 * might be linked from another article about WWII.
 * might be linked from a passage discussing a particular development in the metric system which occurred in that year.

Commemorative days (Saint Patrick's Day) are not considered month-and-day items for the purposes of the above.

Units of measurement that are not obscure
Generally, a unit should be linked only if it is likely to be obscure to many readers or is itself being discussed. For example, the troy ounce, bushel, hand, candela, knot, mho, or millibarn might be considered obscure even if they are well-known within their field of use. Other units may be obscure in some countries even if well known in others.

External links section
Wikipedia is not a link collection, and an article comprising only links is contrary to what the "what Wikipedia is not" policy dictates.

Syntax
The syntax for referencing a web address is simple. Just enclose it in single brackets with a space between the URL and the text that will be displayed when the page is previewed or saved:

The text will display as:
 * Text to display

The URL must begin with either  or   (preferring , where available), or another common protocol, such as   or. If no protocol is used, the square brackets will display normally – [like this] – and can be used in the standard way.

In addition, putting URLs in plain text with no markup automatically produces a link, for example  → https://www.example.org/. However, this feature may disappear in a future release. Therefore, in cases where you wish to display the URL because it is intrinsically valuable information, it is better to use the short form of the URL (domain name) as the optional text:  produces example.org.

Citations templates such as should not be used in the   section. External link templates such as are used instead of citation templates.

Link titles
Embedded HTML links within an article are a now-deprecated way to supply a bare URL as a source within an article, by simply enclosing the URL in square brackets, like this:  →. However, you should add a descriptive title when an external link is offered in the References, Further reading, or External links sections. This is done by supplying descriptive text after the URL, separated by a space and enclosing it all in square brackets.

For example, to add a title to a bare URL such as  (this is rendered as https://en.wikipedia.org/), use the following syntax:   (this is rendered as "an open-content encyclopedia").

Generally, URLs and domain names are ugly and uninformative; it is better for a meaningful title or description to be displayed rather than the URL or domain itself. For example, European Space Agency website is much more reader-friendly than http://www.esa.int/ESA. There may be exceptions where the domain name is well known or is also the company or publication name. When a URL or domain name is given, putting both a plain-English title or description and the URL will often be more informative: for example, European Space Agency website, www.esa.int.

If the URL or domain name displayed, make it as simple as possible; for example, if the   is superfluous, remove it (but be sure to check in preview mode first). Many but not all sites can be trimmed of a leading "www."; test it to be sure. Use camel case to make a displayed domain more readable, e.g. WashingtonPost.com versus washingtonpost.com.

The "printable version" of a Wikipedia article displays all URLs in full, including those given a title, so no information is lost.

URLs as embedded (numbered) links
Without the optional text, external references appear as automatically numbered links: For example,

is displayed like this:
 * 

Numbered links of this type used to be used after the punctuation, like this, with a full citation given in the References section. This style of referencing is now deprecated, because such links are susceptible to link rot. See Citing sources and Verifiability for more information.

Position in article
Embedded links that support information in an article are positioned in the same manner as any other reference in the article, following the usual standards about citation formatting and placement in relation to punctuation.

Links that are not used as sources can be listed in the External links section, like this:



As with other top-level headings, two equal signs should be used to mark up the external links heading (see ). External links should always be the last section in an article. It precedes categories and some kinds of navigation templates.

If there is a dispute on the position of an embedded link, consider organizing alphabetically.

Non-English-language sites
Webpages in English are highly preferred. Linking to non-English pages may still be useful for readers in the following cases:
 * When the website is the subject of the article
 * When linking to pages with maps, diagrams, photos, tables (explain the key terms with the link, so that people who do not know the language can interpret them)
 * When the webpage contains information found on no English-language site of comparable quality, and is used as a citation (or when translations on English-language sites are not authoritative).

If the language is one that most readers could not be expected to recognize, or is for some other reason unclear from the name of the publication or the book or article or page title, consider indicating what language the site is in.
 * Example: Koha Jonë, an Albanian-language newspaper from Tirana
 * Example: El País, a Spanish-language newspaper from Madrid

You can also indicate the language by putting a language template after the link. This is done using Template:In lang by typing. For example, displays as:. See list of ISO 639 codes.

When using one of the or  templates, instead of the  template, use the language parameter. This parameter accepts language names or language codes; see this list of supported names and codes. (Use of language codes is to be preferred because cs1|2 automatically renders language names in the language of the local Wikipedia.)

File type and size
If the link is not to an HTML or PDF file (the latter is identified automatically by the software with an icon like this: ), identify the file type. Useful templates are available: DOClink, RTFlink. If a browser plugin is required to view the file, mention that as well. If a link is to a PDF file but doesn't end with, you can put a   at the end to flag it as a PDF.

If the link is to a very large page (considering all its elements, including images), a note about that is useful since someone with a slow or expensive connection may decide not to visit it.

Linking
Interwiki links can take the form of:
 * which appears as: article

The pipe symbol suppresses the prefix:
 * → article

Adding text after the pipe allows either the same or a different text (with no prefix):
 * → article
 * → Any text

To avoid reader confusion, inline interlanguage, or interwiki, linking within an article's body text is generally discouraged. Exceptions: Wiktionary and Wikisource entries may be linked inline (e.g. to an unusual word or the text of a document being discussed), and Interlanguage link template may be helpful to show a red link accompanied by an interlanguage link if no article exists in English Wikipedia.

Floating boxes
Floating boxes for links to articles in other Wikimedia Foundation projects such as Wiktionary and Wikiquote can be done with special link templates such as. These will display as a box with a logo. Similar templates exist for some free content resources that are not run by the Wikimedia Foundation. These boxes are formatted in light green to distinguish them from Wikipedia's official sister projects. A list of such templates can be found at List of templates linking to other free content projects.

Link maintenance
Linking and continual change are both central features of Wikipedia. However, continual change makes linking vulnerable to acquired technical faults, and to the later provision of different information from that which was originally intended. This is true of both "outgoing" links (from an article) and "incoming" links (to an article).
 * Outgoing links: These should be checked from time to time for unintended changes that are undesirable. If the opportunity arises to improve their formatting, appropriateness, and focus, this should be done.
 * Incoming links: Creating an article will turn blue any existing red links to its title. (Proper redlinks are created only in the hope that an article will eventually be written.) Therefore, when creating an article, it is wise to check "What links here" to identify such redlinks, if any, and that they are appropriate.

Buttons
Buttons should not be used in articles. If the desire is to "navigate" a reader to a new page, taking them away from the current page, a link is preferred. Buttons are used within Wikipedia to trigger an "action", such as or  or  or.