8David Greenawa. Intra-lndustry Trade,lntra-Firm Trade and European Integration: Evidence,Gains and Policy Aspects [J]. Journal of Common Market Studies, 1987,26(2) : 153 - 172.
9Verdoom, P. J. The Intra-Bloc Trade of Benelux. Economic Con- sequences of the Size of Nations. London, 1960(2):291 - 329.
10Linder S. B. An Essay on Trade and Transportation [M].Stock holm: Upsala, 1961.