German, D. A. “Notes on Taxonomy of Erysimum (Erysimeae, Cruciferae) of Russia and Adjacent States. I. Erysimum Collinum and Erysimum Hajastanicum”. Turczaninowia 17, no. 1 (1): 10–32. Accessed August 12, 2025. https://turczaninowia.asu.ru/article/view/655.