User talk:Davidharpy

Hello, I'm Materialscientist. I noticed that you made a change to an article, but you didn't provide a reliable source. It's been removed and archived in the page history for now, but if you'd like to include a citation and re-add it, please do so! If you need guidance on referencing, please see the referencing for beginners tutorial, or if you think I made a mistake, you can leave me a message on my talk page. Thank you. Materialscientist (talk) 21:38, 12 August 2014 (UTC)

Please do not add or change content without verifying it by citing a reliable source. Please review the guidelines at Citing sources and take this opportunity to add references to the article. Thank you. Materialscientist (talk) 23:16, 12 August 2014 (UTC)