Properly acknowledging sources
When should I cite a source?
You should cite a source whenever you quote, paraphrase, or summarize someone else's work, or when you use facts, ideas, data, or visuals that are not "common knowledge" (for example, the freezing point of water is common knowledge; the number of people worldwide suffering from HIV is not). Apply the “common knowledge” test. But also remember that what constitutes common knowledge will vary among different audiences and situations. What is well understood among a group of research physicists may be unfamiliar to chemical engineers. If you’re wondering about whether to cite a source, ask your teacher or mentor. As a general rule, when in doubt, cite; it’s better to err on the side of caution. Citing a source not only gives credit to those you’re borrowing from; it strengthens your own work by making it more credible, and showing how it is supported in the existing literature.

How should I cite a source?
Citations styles vary from field to field. Although all citations generally include the same information (e.g., author, title, date, publisher, volume, issues, pages), different fields or professions have slightly different conventions for citing sources within a document and listing sources at the end. These links provide some guidance for the different styles.

MLA
APA
Chicago
CBE
IEEE

Generic citation of electronic sources for different disciplines:
http://www.cc.columbia.edu/cu/cup/cgos/idx_basic.html

Useful links

For a comprehensive discussion of incorporating information from sources and citation and reference formats, see:

Harvey, Gordon. Writing From Sources. Harvard University. 1995. September 28 2002. <http://www.fas.harvard.edu/~expos/sources/>

This source distinguishes among several different citation styles here: <http://www.fas.harvard.edu/~expos/sources/app_b.html#articleother>

For guidance in evaluating and citing Internet sources, see:
Harnack, Andrew and E. Kleppinger. Online! A reference guide to using Internet sources. 2001. 28 Sep. 2002. <http://www.bedfordstmartins.com/online/index.html>