C. W.  Lukhoba, Simmonds, M. S. J., and Paton, A. J., ?Plectranthus: a review of ethnobotanical uses?, J Ethnopharmacol, vol. 103, pp. 1?24, 2006.

A. J.  Paton, Springate, D., Suddee, S., Otieno, D., Grayer, R. J., Harley, M. M., Willis, F., Simmonds, M. S. J., Powell, M. P., and Savolainen, V., ?Phylogeny and evolution of basils and allies (Ocimeae, Labiatae) based on three plastid DNA regions?, Molecular Phylogenetics and Evolution, vol. 31, pp. 277?99, 2004.