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.
♦ ²NUTRIENT COMPOSITION OF PLANTS MOST FAVOURED BY BLACK RHINOCEROS (DICEROS BICORNIS) IN THE WILD, K. GHEBREMESKEL, G. WILLIAMS, R. A. BRETT, R. BUREK and L. S. HARBIGE, Comp. Biochem. Physiol. Vol. 98A, No. 3/4, pp. 529-534, 1991