Even though it might seem sensible to cite that chapter as one would cite a chapter from an edited book , doing so could cause confusion. If you were to cite a chapter from an authored book in this manner, most of the information from the book reference templates at the bottom of page 202 in the Publication Manual would be maintained, with the names of the book's primary authors in the editor position. However, because you would be crediting them as authors and not as editors, you would need to delete the Eds. in parentheses. Authored books that contain chapters written by other contributors are relatively uncommon, and APA Style users are so accustomed to the format for citing a chapter in an edited book that this slight change might lead your readers to assume that you are incorrectly citing an edited book by accidentally leaving out the Eds. component. Although this may not seem like such a big deal, it could cost a student a few points for not following proper APA Style format. Or, if you're publishing your paper in a journal, you could find yourself battling with a prickly copyeditor.
One author: Gould, S. J., 1983, Hen's Teeth and Horse's Toes, W. W. Norton, New York City, 413 p. Two or more authors: Ingmanson, D. E. and Wallace, W. J., 1985, Oceanography: An Introduction, Wadsworth, Belmont, CA, 530 p. For Articles or Chapters with separate authors from a Book or Compilation List the author(s) of the article using the same format given above for books, then give the year, the title of the article or chapter (no quotes, italics or underlines), then the name(s) of the editor(s) of the book or compilation, followed by "ed." or "eds.". Then put the title of the book (in italics if possible), the publisher, the city, and the page numbers where the article can be found: Rodgers, J., 1983, The life history of a mountain range-- Appalachians, in Hsu, K. J., ed., Mountain Building Processes, Academic Press, Orlando, p. 229-243. For an Article from a Journal or Magazine List the author(s) of the article using the same format given above for books, then give the year, the title of the article or chapter (no quotes, italics or underlines), then the title of the journal or magazine (in italics if possible), the volume number of the journal (do not use the publication date), and page numbers where the article can be found: One author: Maddox, J., 1987, The great ozone controversy, Nature, v. 329, p. 101. Two or more authors: Vink, G. E., Morgan, W. J., and Vogt, P. R., 1985, The Earth's hot spots, Scientific American, v. 252, p. 50- 57. For Internet sources Give the author's last name and initials (if known) and the date of publication (or last modification). Next, list the full title of the work (. the specific web page), and then the title of the complete work or site (if applicable) in italics (if possible). Include any version or file numbers, enclosed in parentheses. Most important, provide the full URL to the resource, including the protocol, host address, and the complete path or directories necessary to access the document. Be sure to spell this out exactly! (best to use an electronic "copy" from the "location" box of your browser and "paste" into your word processor). Finally specify the date that you last accessed the site, enclosed in parentheses. Focazio, ., Welch, ., Watkins, ., Helsel, ., and Horn, ., 1999, A retrospective analysis on the occurrence of arsenic in ground-water resources of the United States and limitations in drinking-water-supply characterizations, . Geological Survey Water-Resources Investigation Report 99-4279, http:///trace/pubs/wrir-99-4279/ (August 1, 2000) Adapt these formats as necessary for other types of sources, including unpublished reports or manuscripts -- just be sure to include sufficient information that your readers could find or obtain these sources themselves, if need be.