Encyclopedias contain brief factual articles on many subjects. There are two types of encyclopedias -- general and subject.
Use wisely and with a bit of skepticism! Verify using other possibly more reliable sources. Professors at WPI generally don't want to see wikipedia references in bibliographies.
scholars in the field, academics or researchers.
always cited with many references and/or footnotes.
long and in-depth research
sometimes edited, with multiple authors, look for university presses for scholarly books.
Encyclopedias are available in print and now, many are available online.
Example hardcopy encyclopedia reference citation in American Psychological Association (APA)style:
Yang, G. W. (2009). Thermodynamic and kinetic theories of nanowire growth. In Encyclopedia of nanotechnology(Vol. 1, pp. 201-235) . New York, NY: Nova Science Publishers, Inc.
Example electronic encyclopedia reference citation in American Psychological Association (APA) style:
Feminism. (2011). In Encyclopædia Britannica. Retrieved from http://www.britannica.com/EBchecked/topic/724633/feminism