Key points are not available for this paper at this time.
Jay Belsky, David Eggebeen, Early and Extensive Maternal Employment and Young Children's Socioemotional Development: Children of the National Longitudinal Survey of Youth, Journal of Marriage and Family, Vol. 53, No. 4 (Nov., 1991), pp. 1083-1098
Belsky et al. (Fri,) studied this question.