求英文文献一篇：
The Measurement of Productive Efficiency，
M. J. Farrell Journal of the Royal Statistical Society. Series A (General), Vol. 120, No. 3 (1957), pp. 253-290
(article consists of 38 pages) Published by: Blackwell Publishing for the Royal Statistical Society Stable URL: http://www.jstor.org/stable/2343100 JSTOR好像有的，请图书馆有购买该资源的同学帮忙一下~~，再此先谢过了~~