Didukh, Yakiv, Olga Chusova, and Olga Demina. 2018. “Syntaxonomy of Chalk Outcrop Vegetation of the Order Thymo Cretacei-Hyssopetalia Cretacei”. Hacquetia 17 (1). https://ojs.zrc-sazu.si/hacquetia/article/view/6719.