BioStor
 | Flavonoid Diversity in Relation to Systematics and Evolution on the Tarweeds William J Crins and Bruce A Bohm (1990) Annals of the Missouri Botanical Garden 77: 73-83 |
 | Biodiversity and Cytogenetics of the Tarweeds (Asteraceae: Heliantheae- Madiinae) Donald W Kyhos, Gerald D Carr and Bruce G Baldwin (1990) Annals of the Missouri Botanical Garden 77: 84-95 |