Valchev, Hristo, and Ekaterina Kozuharova. 2022. “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 (4). Sofia, Bulgaria:527-35. https://doi.org/10.7546/CRABS.2022.04.07.