Key points are not available for this paper at this time.
Jeroen Smits, Wout Ultee, Jan Lammers, Educational Homogamy in 65 Countries: An Explanation of Differences in Openness Using Country-Level Explanatory Variables, American Sociological Review, Vol. 63, No. 2 (Apr., 1998), pp. 264-285
Smits et al. (Wed,) studied this question.