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.
♦ ²{ECOLOGICAL SHIFTS IN SYMPATRY: KALAHARI FOSSORIAL LIZARDS (TYPHLOSAURUS), Raymond B. Huey, Eric R. Pianka, Michael E. Egan, and Larry W. Coons, Ecology (1974) 55: pp. 304-316