Jonathan Levy D. and Peter Pitsch K.. 1985. . “‘Statistical Evidence of Substitutability Among Video Delivery Systems’. ”. In Video Media Competition: Regulation, Economics and Technology . , Edited by: Eli Noam M.. p. 56––92. . New York : : Columbia University Press. .
D. Gray and C. Grant, Cable Television in Western Europe: A Licence to Print Money? EIU Limited, London, 1983
See e.g. R. Noll, M. Peck and J. McGowan, Economic Aspects of Television Regulation, Brookings, Washington, DC, 1973 and J.K. Webb, The Economics of Cable Television, Lexington Books, Lexington, 1983.