How do I reference different parts of a book which is made up of information from external sources?
Answer
It sound like you have an edited book. Usually there is theme to the book and individual chapters written by different authors addressing different aspects of the theme. There is usually one or more editors who are in charge of compiling the work.
From the Publication Manual of the American Psychological Association (pp. 185-186, & 203), these are the parts you need, and an example, to create a citation for an edited book.
Author of the chapter: Vye, C., Jr.
Last name first. First and middle name always represented by initials.
Year of publication: (2007).
Date the book was published. Examine the title page or the title page verso (backside) to determine the date of publication. Place in parentheses with a period following.
Title & subtitle of the chapter: Managing anxiety and related conditions: Solutions and effective approaches.
Title and subtitle are separated by a colon. Capitalize only the first word of the title and subtitle, and any proper nouns. End with a period.
Editor(s) of book: In S. F. Smith, D. J. Duell, & B. C. Martin (Eds.),
Include the word "In" before the editor(s). List names of editors with initials for the first and middle names followed by their last names. Place an ampersand (&) before the last name followed by Eds. in parentheses (or Ed. if there is only one) with a comma after the parentheses.
Title & subtitle of the book: Under pressure and overwhelmed: Coping with anxiety in college
Title and subtitle are separated by a colon. Capitalize only the first word of title and subtitle, and any proper nouns. Italicize title and subtitle. No period!
Page numbers: (pp. 53-67).
Page numbers of the chapter preceded by pp. Place in parentheses. Close with a period.
Place of publication: New York, NY:
List the city and state of the publisher's location. Use the standard postal abbreviations for states. For publishers outside the United States list the city and country. Separate place from publisher with a colon. If more than one city is given, use the first city listed or, if specified, the name of the publisher's home office. Separate from publisher with a colon.
Publisher: Praeger.
Shorten publisher's name to most concise form. End the citation with a period.
Here it is strung together to make the citation.
Vye, C., Jr. (2007). Managing anxiety and related conditions: Solutions and effective approaches. In S. F. Smith, D. J. Duell, & B. C. Martin (Eds.), Under pressure and overwhelmed: Coping with anxiety in college (pp. 53-67). New York, NY: Praeger.