The Nuremberg Code (1949):
http://ohsr.od.nih.gov/guidelines/nuremberg.html

The Universal Declaration of Human Rights:
http://www.un.org/en/documents/udhr/

Charter of the United Nations:
http://www.un.org/en/documents/charter/

The Belmont Report: Ethical Principles and Guidelines for the Protection of Human Subjects
http://ohsr.od.nih.gov/guidelines/belmont.html

The Office of Human Subjects Research at the National Institutes of Health:
http://ohsr.od.nih.gov/

National Association of Social Workers: Code of Ethics:
http://www.socialworkers.org/pubs/code/default.asp

National Statement on Research Integrity in Social Work:
http://www.cswe.org/NR/rdonlyres/B69B1FCB-8773-4CAA-8846-A28F4658090A/0/csweORIbrochure.pdf

Office of Human Subjects Protection. US Department of Health and Human Services:
http://www.hhs.gov/ohrp/humansubjects/guidance/45cfr46.htm

Web Center for Social Research Methods:
http://www.socialresearchmethods.net/

Practical advice from working researchers:
http://www.4researchers.org/