8Fredoun, Z, and Ahmadi-Esfahani., (2006) "Constant Market Shares Analysis: Uses, Limitations and Pros- pects," Australian Journal of Agricultural and Resource Economics 50 (4) , 510-526.
9TINBERGEN J. Shaping the world economy: sugges- tions for an international economic policy [R] . 1962.
10BERGSTRAND J H. The gravity equation in internation- al trade: some mi foundations and empirical evidence [J]. The review of economics and statistics, 1985 : 474-481.