Cita APA

Collier, P., Hoeffler, A., & Söderbom, M. (2001). On the Duration of Civil War. World Bank.

Citación estilo Chicago

Collier, P., A. Hoeffler, and M. Söderbom. On the Duration of Civil War. World Bank, 2001.

Cita MLA

Collier, P., et al. On the Duration of Civil War. World Bank, 2001.