HEYWOOD, V.H. (ed.). 1978. Flowering plants of the world. Oxford University Press, Oxford, London, Melbourne.

HEYWOOD, V.H. (ed.). 1978. Flowering plants of the world. Oxford University Press, Oxford, London, Melbourne.
http://pza.sanbi.org/references/heywood-vh-ed-1978-flowering-plants-world-oxford-university-press-oxford-london-melbourne