Njunwa, K. ., G. Mwaiko, B. Kilonzo, and J. . Mhina. “Studies on the Seasonal Patterns of Rodent, Flea and Plague Outbreaks in the Western Usambara Mountains, North-East Tanzania”. Tanzania Veterinary Journal, vol. 7, no. 2, Mar. 1985, pp. 16-27, http://tvj.sua.ac.tz/vet2/index.php/TVJ/article/view/305.