4Tinbergen,Jan,"Shaping the World Economy:Suggestionsfor an Interna-tional Policy",[M].New York:TwentiethCentury Fund,1962.
5Anderson,James E.,"A Theoretical Foundation for theGravity Equation",American Economic Review,Vol.1979(1),:106-116.
6Berg strand,Jeffrey,"The G rav ity Equation in Inte rnation-al Trade:Some M icroeconomic Foundations and EmpiricalEv idence",The Review o f Econom ics and Statistics,1985(8),:474-481.
7Eaton,Jonathan,and Samuel Kortum,Techno logy,Geogra-phy,and Trade,Econometrical,2002(5):1741-1779.
8Deardorff,A lan V.,"Determinants of Bilateral Trade:DoesGravity Work in a Neoclassical World?"NBER WorkingPaper,1996.
9Helpman,Elhanan,and Paul R.Krugman,"Market Struc-ture and Foreign Trade:Increasing Returns,ImperfectCompetition and the International Economy",Cambridge,MA:M IT Press,1985.
10Anderson,Jam es E.,and Er ic vanW incoop,"Grav ity with G rav itas:A So lu tion to the Border Puzzle",Am ericanE c(onom ic Rev iew),2003.
