BioStor
 | Analysis of the Flora of Mediterranean and Saharan Africa P Quezel (1978) Annals of the Missouri Botanical Garden 65: 479-534 |
 | The genera of Brassiceae (Cruciferae; Brassicaceae) in the southeastern United States Ihsan Al-Shehbaz (1985) Journal of the Arnold Arboretum 66: 279-351 |