2Lee E S.A theory of migration[J].Demography,1966,3(1):47-57.
3Spaan E.Labour circulation and socioeconomic transformation:he case of east java,indonesia[R].The Hague:Netherlands Interdisciplinary Demographic Institute,1999.
4Hugo G J.Migration as a survival strategy:the family dimension of migration[C]//Proceedings of the United Nations expert group meeting on population distribution and migration,Santa Cruz,Bolivia,1993.New York:Department of Economic and Social Affairs,1998:139-149.