See Blau F and Kahn L (1997), "Swimming Upstream: Trends in the Gender Wage Differential in the 1980s", Journal of Labor Economics, Vol. 15, No. 1, Part 1 (Jan., 1997), pp. 1-42 ]
Seetõttu peavad naised nö vastuvoolu ujuma ja ebasoodsate suundumuste vastu võitlema.. Vt Blau, F. ja Kahn, L., „Swimming Upstream: Trends in the Gender Wage Differential in the 1980s", Journal of Labor Economics, 15. kd, nr 1, 1. osa (jaanuar 1997), lk 1-42. ]