Key points are not available for this paper at this time.
Lawrence W. Kenny, Lung-Fei Lee, G. S. Maddala, R. P. Trost, Returns to College Education: An Investigation of Self-Selection Bias Based on the Project Talent Data, International Economic Review, Vol. 20, No. 3 (Oct., 1979), pp. 775-789
Kenny et al. (Mon,) studied this question.