4Cowgill, P. 1974, Aging and Modernization: A Revision of Theory, In J, Gubrium (Ed,) ,later life: Community and Environmental Policies(pp, 123- 146),New York: Free Press.
5Cowgill, P. 1974, Aging and Modernization: A Revision of Theory, In J, Gubrium (Ed.) ,later llfe: Community and Enviromaaental Policies(pp, 123 - 146) ,New York: Free Press.
6Du P and P Tu 2000 Population Aging and Old Security . The Changing Population of China , Blackwell Publishers.
7Scott Rozelle, L G ,Minggao Shen, et al 1999 . Leaving China' s Farms: Survey Results of New Paths and Remaining Hurdles to Rural Migration ." Tne China Quartedy.
8Kenneth D Roberts,2001 .The determinants of job choice by rural labor migrants in Shanghai. China Economic Review 12(2001)15 - 39.
9Robert H. Bradley, Robert F. Corwyn. Socioeconomic status and child development [J]. Annual Review of Psychology,2002, (53).
10Vonnie C. Mcloyd. Socioeconomic disadvantage and child development[J]. American Psychologist, 1998, (53).
