英文文献：The Economics and Productivity of Organic versus Non-organic U.S. Dairy Farms
英文文献作者：Nehring, Richard,Gillespie, Jeffrey,Harris, J. Michael Harris
英文文献摘要：
A Stochastic Production Frontier (SPF) model is estimated for U.S. dairy farms to examine the productivity of organic and non-organic dairy farms by system and size. For both systems, size is the major determinant of competitiveness based on various measures of productivity and returns to scale.