Citing a source means that you show, within the body of your text, that you took words, ideas, figures, images, etc. from another place. They are a short way to uniquely identify a published work (e.g. book, article, chapter, web site). They are found in bibliographies and reference lists and are also collected in article and book databases.
Citations consist of standard elements, and contain all the information necessary to identify and track down publications, including:
You must cite:
When in doubt, be safe and cite your source!