Robbins, M. M., Robbins, A. M., Gerald-Steklis, N., & Steklis, H. D. (2007). Socioecological influences on the reproductive success of female mountain gorillas (Gorilla beringei beringei). Behavioral Ecology and Sociobiology, 61(6), 919-931. doi:10.1007/s00265-006-0321-y.