1. Are Purchasing Ethics Being Put to the Test;Cummings;Iron Age,1979
2. Ethical Practices in Purchasing;Forker;Journal of Purchasing and Materials Management,1990
3. R.L. Janson K.I. Warner We Present Your Own Values and Beliefs on Ethical Purchasing Midwest Purchasing Magazine , August, September, October, November 1977
4. Cooperation, Opportunism, and the Invisible Hand: Implications for Transaction Cost Theory;Hill;Academy of Management Review,1990
5. National Association of Purchasing Management Principles and Standards of Purchasing Practice with Accompanying Guidelines 1992