5BAUMOL,WILLIAM J.On the proper cost tests for natural monopoly in a multiproduct industry[J].American Economics Review,1977,67(5):809-822.
6BERG S,TSCHIRHART J.Natural monopoly regulation:principles and practices[M].Cambridge:Cambridge University Press,1988.
7EVANS D S,HECKMAN,JAMES J.A test for subadditivity of the cost function with an application to the Bell system[J].American Economics Review,1984,76(4):613-623.
8GORDON D V,GUNSCH K,PAWLUK CV.A natural monopoly in natural gas transmission[J].Energy Economics,2003,25(5):473-485.
9ELLIG J,GIBERSON M.Scale scope,and regulation in the Texas gas transmission industry[J].Journal of Regulatory Economics,1993,5(1):79-90.
10MANSELL R,CHURCH J.Regulatory alternatives for natural gas pipelines in Canada[R].Calgary:Van Horne Institute,1995.
