4Armstrong M. , The Theory of Access Pricing and Interconnection. Handbook of Telecommunications Economics . Volume I Eds. M. Cave,S. Majumdar,and I. Vogelsang, Amsterdam. North-Holland Press. 2002, pp. 295--384.
5Bain J. S. , Industrial Organization. New York. Harvard University Press, 1959.
6Farrell J. and Saloner G. ,StandardizatiOn, Compatibility, and Innovation. Rand Journal of Economy, Vol. 16, 1986, pp. 70-- 83.
7Rochet J. and Tirole J. ,Two-sided Markets .An Overview. Mimeo, IDEI University of Toulouse, 2004.