Attributes / relations provided by
♦ ¹del Hoyo, J., Elliott, A., Sargatal, J., Christie, D.A. & de Juana, E. (eds.). Handbook of the Birds of the World Alive. Lynx Edicions, Barcelona.
♦ ²Note on Drill (Mandrillus leucophaeus) Ecology and Conservation Status in Korup National Park, Southwest Cameroon, CHRISTOS ASTARAS, MICHAEL MUHLENBERG, AND MATTHIAS WALTERT, American Journal of Primatology 69:1–7 (2007)