| Author | Title | Journal/publisher | Literature ref. no. |
| Bruyns, P.V. (2002) | Monograph of Orbea and Ballyanthus (Apocynaceae-Asclepiadoideae-Ceropegieae) | Systematic Botany Monographs 63 1-196 | 540 |
Note that the process of capturing references from species to the literature and the reverse may be incomplete.
| Species found: 3 |
| Orbea caudata subsp. rhodesiaca |
| Orbea schweinfurthii |
| Orbea valida subsp. valida |