6REINHARD S, LOVELL C A K, THIJSSEN G J. Environ- mental Efficiency with multiple environmentally detrimental variables: estimated with SFA and DEA[J]. European Journal of Operational Research, 2000,121 : 287 - 303.
7MANDAL S M,MADHESWARAN S. Environmental efficien- cy of the Indian cement industry : An interstate analysis[J]. En ergy Policy,2010,38:1 108-1 118.
8LI H W,ZHOU D Q,SUN Y L. To forecast the investment m the treatment of the environmental pollution of China by GM (1,1) [C]. Proceeding of 2007 IEEE International Conference on Gray Systems and Intelligent Services, 2007:423-427.
9白仲林,2009:《面板数据的计量经济分析》,南开大学出版社.
10Ahn & Powell (1993), "Semiparametric estimation of cen- sored selection models with a nonparametric selection mechanism", Journal of Econometrics 58:3-29.