6Grossman,GM and A.B.Krueger.Environmental Impacts of A North American Free Trade Agreement,CEPR Discussion Paper No.644 (London:Center for Economic Policy Research),1992.
7Stern D.I.,2004.The rise and fall of the environmental Kuznets curve.World Development,8,1419~1439.
8Ekins S.The Kuznets Curve for the environment and economic growth:examining the evidence.Environment Planning,1997,29:805~830.