Hernández-Barón, Gerald Matus, Diana Isabel Trujillo Juárez, and Victor W. Steinmann. “Polystemma stevensii (Apocynaceae, Asclepiadoideae), a New Species from Michoacán, Mexico”. Phytotaxa 613, no. 2 (September 13, 2023): 194–200. Accessed December 6, 2025. https://phytotaxa.mapress.com/pt/article/view/phytotaxa.613.2.9.