1. American Psychological Association. Ethical Principles in the Conduct of Research with Human Participants. Washington, D.C.: American Psychological Association, 1992.
2. (Also see APA's Ethical Principles and Code of Conduct at http://www.apa.org/ethics/code.html)
3. and Experimental and Quasi-Experimental Designs for Research. Chicago: Rand McNally, 1966.