Template:Robson, 2002
- Robson, N.K.B. 2002. Studies in the genus Hypericum L. (Guttiferae) 4(2). Section 9. Hypericum sensu lato (part 2): subsection 1. Hypericum series 1. Hypericum. Bulletin of The Natural History Museum. Botany Series 32(2): 61–123. BHL