Linder, H.P., Dlamini, T., Henning, J. & Verboom, G.A. 2006. The evolutionary history of Melianthus (Melianthaceae). American Journal of Botany 93(7): 1052–1064.
http://pza.sanbi.org/references/linder-hp-dlamini-t-henning-j-verboom-ga-2006-evolutionary-history-melianthus