Originally written in 1906, this tome has a rich history of providing quality guidelines for citing works and creating bibliographies. The BU Libraries have a subscription to the full online version. The website also offers a citation quick guide that has many examples. The 17th edition is the most recent, published in 2017.
The official style manual for the National Library of Medicine (NLM), and suggested when citing documents from the associated databases MedLine and PubMed. The online edition supercedes the print edition as the most up to date.