References

For Cephalanthus

Ridsdale, C.E. 1976. A revision of the tribe Cephalantheae (Rubiaceae). Blumea 23: 177-188. Google Scholar

Rogers, G.K. 1987. The genera of Cinchonoideae (Rubiaceae) in the southeastern United States. J. Arnold Arb. 68: 137-183. Google Scholar