Barbosa, C. V. D. O., Pereira, A. S. D. S., Viana, P. L., & Simões, A. O. (2019).

A taxonomic revision of Geissospermum (Apocynaceae, rauvolfioid)

. Phytotaxa, 420(2), 157–178. https://doi.org/10.11646/phytotaxa.420.2.3