1A.D.Mathios & R.P.Rogers,"The Impact of Alternative Forms of State Regulation of AT &T Direct-Dial,Long-Distance Telephone Rates,"RAND Journal of Economics,20 (Autumn 1989),437~453
2P.L.Joskow & N.L.Rose,"Economic Regulation and its Effects,"in R.Schmalensee & R.D.Willig (eds.),Handbook of Industrial Organization,Volume 2,Amsterd am.North-Holland,1989,Ch.25