7W B REDDAWAY. Royal Economic Society[J]. The Economic Journal, 1963 (9).
8A B ALBARRAN,J DIMMICK. Concentration and E- conomics of Multiformity in the Communication Indus- tries[J].Journal of Media Economics, 1996,4(9).
9J N ROSSE. Daily Newspaper, Monopolistic Competi- tion and Economies of Scale [J]. The American Eco- nomic Review, 1967, 3(2).
10ROBERT B. EKELUND, THOMAS KOUTSKY. Market Power in radio markets: An Empirical Analysis of Local and National Concentration[J]. The Journal of Law & Economics, 2000 (1).
