T. G.  Leonova, ?Rod Hypericum L. (Hypericaceae) vo flore Kavkaza. (De genere Hypericum L. (Hypericaceae) in flora Caucasi.)?, Novosti Sist. Vyssh. Rast., vol. 28, pp. 117-125 (1991) -, 1991.

P. V.  Arrigoni, ?Le piante endemiche della Sardegna: 199.?, Boll. Soc. Sarda Sci. Nat., vol. 28, pp. 311-316 (1990-1991 publ. 1991) - illus., 1991.

C.  Reynaud, ?Etude des teguments seminaux (observes au M.E.B.) de quelques  Hypericum (Guttiferae) mediterraneens: 2. (Study of the seed-coat (investigated with S.E.M.) of some mediterranean species of Hypericum (Guttiferae): 2.)?, Bull. Mus. Nation. Hist. Nat., B, Adansonia, vol. 13, pp. 183-195 (1991) - illus., 1991.

A.  Boratynski, Tomlik, A., and Zielinski, J., ?Hypericum aegypticum L. and Dianthus fruticosus L. on the island of Zakinthos (Greece).?, Arbor. Kornickie, vol. 34, pp. 55-63 (1989 publ. 1991) - illus., 1991.