3Coase R. H, Fowler, R. F-The Pig-cycle in Great Britain: An Explanation [J]. Economica, 1937, (13).
4Ezekiel M. The Cobweb Theorem, Quarterly [J]. Journal Economics, 1938, (02).
5Futrell G.A, Mueller A.G. , Grimes G. Understanding Hog Production and Price Cycles[R]. Pur- due University Cooperative Extension Service, West Lafayette, Indiana, 1989.