Steyn, H.M. & Wyk, A.E.V. (2017)

Taxonomic notes on Acanthopsis Harv. (Acanthaceae, tribe Acantheae): the group with trifid bracts

. Phytotaxa 295 (3): 201–217. https://doi.org/10.11646/phytotaxa.295.3.1