Crawford, D. J.; Mort, M. E. (2005). "Phylogeny of Eastern North American Coreopsis (Asteraceae-Coreopsideae): insights from nuclear and plastid sequences, and comments on character evolution". American Journal of Botany. 92 (2): 330–6. doi:10.3732/ajb.92.2.330. PMID21652409.
Crawford, D. J.; Mort, M. E. (2005). "Phylogeny of Eastern North American Coreopsis (Asteraceae-Coreopsideae): insights from nuclear and plastid sequences, and comments on character evolution". American Journal of Botany. 92 (2): 330–6. doi:10.3732/ajb.92.2.330. PMID21652409.