A book appendix has a specific purpose -- it contains information related to the topic, but the material is very detailed or not directly pertinent. The reader might find it distracting if it were included in the text. The "Publication Manual of the American Psychological Association, (6th ed.)" offers guidelines for referencing appendices.
After discussing information in an appendix from an outside source, include an in-text citation within parentheses. Insert the author's name, a comma and the publication year, such as (Doe, 2012). If you mention the author's name in text, omit it from the parentheses. If you reference an appendix you have created and included at the end of your paper, simply mention it by name; for instance: Appendix B.
Include an in-text citation of an appendix from an outside source on the References page. Begin with the author's last name, a comma, initials and a period. Put the publication year inside parentheses. Add a period. Insert "Appendix" without quotation marks, the identifying letter of the appendix, "of" without quotation marks and the italicized book title in sentence case. Add a period. Indicate the publication location. Add a colon, then insert the publisher's name. Finish with a period; for example: Doe, J. J. (2012). Appendix C of The history of language. New York: Linguistics Works, Inc.