7G.C.Pentzaropoulos,D.I.Giokas.Comparing the operational effciency of the main European telecommunications organizations: A quantitative analysis. Telecotranunications Policy, 26(2002) : 595-606.
8Noel D.Uri.Changing productive effciency in telecommunicationsin the United States.Production Economics, 72(2001):121 -- 137.
9Sun wen-bin, Sun Wei.Non-parametric Measurement and decomposition of Production Resource Allocation Efficiency.Natutal science Journal of Jilin University of Technology, 31(2002) : 45-50.
10Noel D.Uri.Technical efficiency, allocative efficiency, and the impact of in centive regulation in telocommunications in the United States. Structural Change and Economic Dynamics, 12(2001) :59-73.