1 Caplow, T., Hicks, L., & Wattenberg, B. J. (2001). The first measured century: An illustrated guide to trends in America, 1900-2000. La Vergne: TX: AEI Press.
2 Daly, M., and Wilson, M. (1983). Sex, evolution, and behavior. Belmont, CA: Wadsworth.
3 Gurley Brown, H. (1962). Sex and the single girl. New York: Bernard Geis.
4 Cashdan, E. (2008). Waist-to-hip ratios across cultures: Trade-offs between androgen- and estrogen-dependent traits. Current Anthropology, 49, 1099-1107.
5 Klinenberg, E. (2012). Going solo: The extraordinary rise and surprising appeal of living alone. New York: Penguin.
6 Barber, N. (2017 b). Cross-national variation in attitudes to premarital sex: Economic development, disease risk, and marriage strength. Cross-Cultural Research, 1-15. DOI: 10.1177/1069397117718143