American Anthological Association (AAA) Style now adheres fully to the current edition of the Chicago Manual of Style (Author-Date).
American Chemical Society (ACS) Style is used in chemistry.
AP Style is used by journalists; it is the style you'll encounter most often in the popular press.
The Annals of the Association of American Geographers follows the citation rules outlined in the Chicago Manual of Style (CMS). The following style sheets, may be used as supplements to the CMS to provide guidance when formatting citations according to AAG rules.
Institute for Electrical and Electronics Engineers (IEEE) style is used often in electronic engineering and computer sciences.