Swanepoel, W. 2012.

Euphorbia melanohydrata subsp. conica (Euphorbiaceae), a new subspecies from Namibia, with notes on the identification of similar medusoid euphorbias

. Phytotaxa. 62, 1 (Aug. 2012), 33–38. DOI:https://doi.org/10.11646/phytotaxa.62.1.7.