It looks like you're using an Ad Blocker.
Please white-list or disable AboveTopSecret.com in your ad-blocking tool.
Some features of ATS will be disabled while you continue to use an ad-blocker.
This guide on avoiding plagiarism gives some advice on that topic:
Originally posted by operation mindcrime
Strictly speaking, if I state that 1+1=2 (which I learned from a math book) I have to link to the source?
Your example would be considered "common knowledge". Determining where the cutoff is in which knowledge is considered common may take some judgement, but if in doubt, personally I'd provide a source.
What Plagiarism Isn’t
1) Common knowledge. One important thing to know is that information considered common knowledge or in the “public domain” does not need to be cited. Certain facts are so well-known that you don’t need to worry about finding verification. For example, saying that “the sun rises in the East and sets in the West” or that there are “fifty states in America” need not be cited.