1. Hall R.L., Hitch C.J , (1939), “Price Theory and Business behaviour”, Oxford Economic Papers N°2, may, p. 12-45
2. Fog B. (1960), “Industrial Pricing Policies. An analysis of Danish manufacturers”, North-Holland Publishing Company, Amsterdam, p. 229.
3. Hayne W.W. “Pricing decisions in a small business”, University of Kentucky Press. p. 3 & 84.
4. Kaplan A., Dirlam J. and Lanzilloti R. (1958),“Pricing in big business- a case of approach”, The Brookings Institution, Washington D.C., p. 344
5. SUSE accounting data base, INSEE, figures related to year 2002 and 2003.