Whenever content from another source is used, it should be attributed. If it is under a compatible open license, attribution is required. One of these templates may be suitable, or they may be used as the basis for an attribution.

If the original source is public domain, then attribution is not required, by law. At Appropedia we still prefer to attribute in such cases, so that readers know the source, and the original author gets appropriate credit.

Fragments up to one or two standard length sentences are not considered copyrightable and do not have to be attributed.[verification needed] However, a notable quote is still worth attributing, even if very brief.