8COELLIT J, PERELMAN S. Technical efficiency of European railway: a distance function approach [ J]. Ap- plied Economics ,2000, 32 ( 15 ) : 1967 - 1976.
9BRUMMER B, GLAUBEN T, Thijssen G. Decomposition of productivity growth using distance function: the case of dairy farms in three European countries [ J]. American Journal of Agricultural Economics, 2002, 84 ( 3 ) :628 - 644.
10PAUL C M J, NEHRING R. Product diversification, production system, and economic performance in U. S. agricultural production [ J]. Journal of Econometrics, 2005, 126:525 - 548.
