Valchev, Hristo, and Ekaterina Kozuharova. “In Situ and Ex Situ Investigations on Breeding Systems and Pollination of Sideritis Scardica Griseb. (Lamiaceae) in Bulgaria”. Proceedings of the Bulgarian Academy of Sciences 75, no. 4 (May 2, 2022): 527–535. Accessed October 28, 2026. https://www.proceedings.bas.bg/index.php/cr/article/view/62.