Csiky, János, and Dragica Purger. 2013. “Herbaceous Periwinkle, Vinca Herbacea Waldst. Et Kit. 1799 (Apocynaceae), a New Species of the Croatian Flora”. Acta Botanica Croatica 72 (2). https://www.abc.botanic.hr/index.php/abc/article/view/759.