Attributes / relations provided by
♦ ¹Breeding and nest site characteristics of the Black-casqued Hornbill Ceratogymna atrata and White-thighed Hornbill Ceratogymna cylindricus in south-central Cameroon, Donald J Stauffer and Thomas B Smith, Ostrich 2004, 75(3): 79–88
♦ ²Feeding Ecology of Mandrills (Mandrillus sphinx) in Campo Animal Reserve, Cameroon, JIRO HOSHINO, PRIMATES, 26(3): 248-273, July 1985
♦ ³Seed dispersal by Ceratogymna hornbills in the Dja Reserve, Cameroon, KENNETH D. WHITNEY, MARK K. FOGIEL, AARON M. LAMPERTI, KIMBERLY M. HOLBROOK, DONALD J. STAUFFER, BRITTA DENISE HARDESTY, V. THOMAS PARKER and THOMAS B. SMITH, Journal of Tropical Ecology (1998) 14:351–371