For Edrastima
Gibbons, K.L. 2020. Hedyotis, Oldenlandia and related genera (Rubiaceae: Spermacoceae) in Australia: New genera and new combinations in an Asian‐Australian‐Pacific lineage. Taxon 69: 515-542. Google Scholar
Rogers, G.K. 1987. The genera of Cinchonoideae (Rubiaceae) in the southeastern United States. J. Arnold Arb. 68: 137-183. Google Scholar
Terrell, E.E. 1991. Overview and annotated list of North American species of Hedyotis, Houstonia, Oldenlandia, and related genera. Phytologia 71: 212-243. Google Scholar
Terrell, E.E., and H. Robinson. 2006. Taxonomy of North American species of Oldenlandia (Rubiaceae). Sida 22: 305-329. Google Scholar
Ward, D.B. 2012a. New combinations in the Florida flora III. Phytologia 94: 459-485. Google Scholar