8Battese G E, Coelli T J. A model for technical inefficiency effects in a stochastic frontier production function for panel data. Empirical e- conomics, 1995,20 (2) :325 - 332.
9Chen Z, Huffman W E, Rozelle S. Farm technology and technical efficiency:Evidence from four regions in China. China Economic Re- view,2009,20(2) :153 - 161.
10Coase R H. The nature of the firm. economica, 1937,4(16) :386 -405.
