8Benjamin, D. , L. Brandt & J. Giles(2005), "The evolution of income inequality in rural China", Economic Development and Cultural Change, 53(4) :769 -824.
9Bound, J. & G. Johnson(1992), “ Changes in the structure of wages in the 1980's: An evaluation of alternative explanations”, American Economic Review, 82 ( 3 ) : 371 - 92.
10Card, D. (1992), "The effect of unions on the distribution of wages", NBER Working Paper, Oct., No. 4195.