6Becker Gary S. Human Capital: A Theoretical and Em- pirical Analysis (2nd ed) [ M ]. New York : Columbia U- niversity Press, 1975.
7Keep Ewart. Market Failure and Public Policy on Train- ing: Some Reasons for Caution [ J ]. Development and Learning in Organizations, 2006, 20 (6).
8Barron John M. , Mark C. Berger and Dan A. Black. Do Workers Pay for On-The-Job Training? [ J ]. The Journal of Human Resources, 1999, 34(2).
9Stevens Margaret. Human Capital Theory and UK Voca- tional Training Policy [ J ]. Oxford Review of Economic Policy, 1999, 15(1).
10Booth Alison L, Marco Francesconi and Gylfi Zoega. U- nions, Work-Related Training, and Wages: Evidence for British Men [ J ]. Industrial and Labor Relations Re- view, 2003, 57(1).