Citations

Appropriate use of reference - use the most relevant part of any paper cited, something that is a direct result of that study, not simply something said in that paper. The textbook comes in handy for general material.
In scientific writing, avoid the use of direct quotations from a source. If you understand the lab, the report should come from you, in your own words. Of course, when you mention specific information, you should cite it.
Proper format in text - Use the Author/Year System. Year follows name always. Never put initials in the citation. Readers can get them in the Literature Cited section.

Examples

One author: Smith (1970) or (Smith 1970)
Two authors: Smith and Jones (1990) or (Smith and Jones 1990).
Three or more authors: Smith et al. (1990) or (Smith et al. 1990)

Placement of parentheses depends on sentence structure, for example:

N. viridula excretes most of its nitrogen in the form of amino acids (Powles et al. 1972).

Eskin (1972) suggests that the clock mechanisms may be sensitive to membrane depolarization changes throughout the day.

Special note: Web sites should not be excessively cited as references because most do not have the authority of peer-reviewed journals. The only exceptions are on-line journals and my lab instructions. Otherwise, not all of your references can be web sites. Such sites should be cited in the author/year format and listed with the author, title and Uniform Resource Locator (URL, or web address). If no author is listed, use Anonymous or the initials of the sponsoring organization, such as NIMH. If no year is listed (look hard), use the current year.
Example:
Coelho, J.R. 1999. Guide to lab reports. http://websites.quincy.edu/~coelhjo/reports.htm