A.Source citation sounds like a technical term, but it's really just recording where you found each piece of information so you — or anyone else — can go back to the original.

Different kinds of sources require different citation styles. For books, record the title, author, publisher and location, year of publication, where you found the book, library call number (if applicable), and the pertinent page numbers, like so: “Carmack, Sharon DeBartolo and Erin Nevius, eds., The Family Tree Resource Book for Genealogists (Cincinnati: Family Tree Books, 2004), 219-220.”