Kalpers, J., Williamson, E. A., Robbins, M. M., McNeilage, A., Nzamurambaho, A., Lola, N., & Mugiri, G. (2003). Gorillas in the crossfire: Population dynamics of the Virunga mountain gorillas over the past three decades. Oryx, 37(3), 326-337. doi:10.1017/S0030605303000589.