Swanepoel, W. (2013)

Euphorbia otjipembana subsp. okakoraensis (Euphorbiaceae), a new subspecies from the Kaokoveld, Namibia, with an amplified description of Euphorbia otjipembana

. Phytotaxa 117 (2): 51–57. https://doi.org/10.11646/phytotaxa.117.2.3