7Krugman,P.Geography and Trade[M].London:MIT Press,1991.
8Lefteris Topaloglou.The Role and Nature of Borders[J].WG1:Borders,2009(14):1-33.
9James Anderson,Liam O'Dowd.Borders,Border Regions and Ter-ritoriality:Contradictory Meanings,Changing Significance[J].Re-gional Studies,1999,33(7):593-604.