Franck, A.R., Lewis, P.A., Oberli, A., Haynes-Sutton, A., Rose, P.E. . & Campbell, K.C.S.E. (2017)

The Jamaican endemic Exostema orbiculatum belongs to Erithalis (Rubiaceae)

. Phytotaxa 297 (3): 273–281. https://doi.org/10.11646/phytotaxa.297.3.6