Didiereaceae: "Cacti of the Old World" (The British Cactus and Succulent Society : 1992)*Rowley, G.D. "The Pachypodium rosulatum aggregate (Apocynaceae) - one species or several?
Didiereaceae: «Cacti of the Old World» (The British Cactus and Succulent Society : 1992)* Rowley, G.D. «The Pachypodium rosulatum aggregate (Apocynaceae) — one species or several?» Bradleya: The British Cactus and Succulent Society Yearbook.