A. M.  Gasanov, ?K ekologicheskoi anatomii Hypericum perforatum L. flory Azerbaidzhana.?, Izv. Akad. Nauk Az. SSR, Biol. Nauk, vol. no. 4, pp. 8 - 14 (1975) -, 1975.

C.  Reynaud, ?Contribution a l'etude cytotaxonomique de quelques Hypericum mediterraneens.?, Biol. Ecol. Medit., vol. 2, pp. 3 - 8 (1975) -, 1975.

R.  Ornduff, ?Heterostyly and pollen flow in Hypericum aegypticum (Guttiferae).?, Bot. J. Linn. Soc., vol. 71, pp. 51-57 (1975), 1975.

P.  Dupuy and Guedes, M., ?Placentation and possible partial stachyospory in Hypericum sect. Eremanthe.?, Flora (Germany), vol. 164, pp. 37-49 (1975)., 1975.