This document discusses the rhetorical purpose of citations in technical writing. Citations place research in the context of existing work, acknowledge conflicts with other findings, and provide evidentiary support for important claims. Different documentation styles exist depending on discipline, company, or publication. Citations can be direct, identifying the author and work, or indirect, citing the work without identifying the author. Common documentation styles include APA, MLA, Chicago, CBE, and IEEE, which differ in placement of citations and formatting of reference lists. All require corresponding entries in a reference list or bibliography with basic elements like author, title, date, and publisher.