1[1]John Fingleton.(1997). "Competition Between Intermediated and Direct Trade and the Timing of Distintermediation". Oxford Economic Papers, 49, 543～ 556.
2[2]Soon-Yong choi, Dale O. Stahl, Andrew E. Whinston. (1997). The Economics of Electronic Commerce, Macmiooan Technical Publishing, Indianapolis, Indiana.
3[3]Andreu Mas-Colell, Michael D. Whinston and Jerry R.Green. (1995). Microeconomic Theory, OxfordUniversity Press, New York.
