Jobling, James A. (2010). The Helm Dictionary of Scientific Bird Names. London: Christopher Helm. pp. 230, 266. ISBN978-1-4081-2501-4.
Kemp, A.C. (2001). "African Grey Hornbill". In del Hoyo, J.; Elliott, A.; Sargatal, J. (eds.). Handbook of the Birds of the World. Vol. 6: Mousebirds to Hornbills. Barcelona, Spain: Lynx Edicions. p. 493. ISBN978-84-87334-30-6.