User talk:Petro Sapriianchuk

August 2019
Hello, I'm DVdm. I noticed that you made a change to an article, Electromagnetic radiation, but you didn't provide a source. I’ve removed it for now, but if you’d like to include a citation to a reliable source and re-add it, please do so! If you think I made a mistake, or if you have any questions, you can leave me a message on my talk page. Thanks. DVdm (talk) 19:34, 19 August 2019 (UTC)

Note: I have added some useful links at the top of your talk page. Regarding your request for help at Help_desk: please have a careful look at one our key policies: wp:verifiability. Cheers. - DVdm (talk) 20:49, 19 August 2019 (UTC)