5David Karemera,Victor lwuagwu oguldeo,Bobby Davis.A Gravity Model Analysis of International Migration to North America [J ] .Applied Economics,2000 (32).
6Casey R.Wannan, Christopher Worswick.Immigrant Earnings Performanc.
7Vijayakumar Ivaturi, Bruno Lanvin, and Hrishi Mohan. Global Mobility of Talents: What Will Make People Move, Stay, or Leave in 2015 and Beyond? [ R]. The Global Information Technology Report 2009,2009:83 -94.