Robbrecht E (1987) The African Genus Tricalysia A. Rich. (Rubiaceae). 4. A Revision of the Species of Sectio Tricalysia and Sectio Rosea. Bulletin Du Jardin Botanique National De Belgique 57: 39-208. doi: 10.2307/3668317.
There is no corrections for Tricalysia griseiflora var. benguellensis yet.