（1）The Elasticity of Foreign Demand for U.S. Agricultural Products: The Importance of the Price Transmission Elasticity
          Maury E. Bredahl, William H. Meyers and Keith J. Collins
          American Journal of Agricultural Economics, Vol. 61, No. 1 (Feb., 1979), pp. 58-63
http://www.jstor.org/pss/1239500

（2）Demand Elasticities for Soybean Meal in the European Community
          Hendrik C. Knipscheer, Lowell D. Hill and Bruce L. Dixon
          American Journal of Agricultural Economics, Vol. 64, No. 2 (May, 1982), pp. 249-253
http://www.jstor.org/pss/1241130

（3）Exchange Rate Uncertainty and the Demand for U.S. Soybeans
          Margot Anderson and Philip Garcia
          American Journal of Agricultural Economics, Vol. 71, No. 3 (Aug., 1989), pp. 721-729
http://www.jstor.org/pss/1242028

先感谢各位热心朋友的相助了！！！！！！