N. K. B.  Robson, ?Studies in the genus Hypericum L. (Guttiferae): 7. Section 29. Brathys (part 1).?, Bull. Brit. Mus. (Nat. Hist.) Bot., vol. 16, p. 106p. (1987) - illus., maps., 1987.

N. K. B.  Robson, ?An Iranian floristic link with Socotra in Hypericum (Hypericaceae).?, Pl. Syst. Evol., vol. 155, pp. 89-92 (1987) -, 1987.