1. Cherlin, A. , Cross-Barnet, C. , Burton, L. M. , & Garrett-Peters, R . (2007). Promises they can keep: Low-income women’s attitudes toward motherhood and marriage (Welfare, Children, & Families: A Three City Study Working Paper 07-02). Retrieved June 4, 2008, from http://web.jhu.edu/threecitystudy/Publications/index_old.html
2. Cohabitation and exchanges of support;Eggebeen;Social Forces,2005
3. Age differentiation and the life course;Elder;Annual Review of Sociology,1975