von Poellnitz, Karl (1936). "Bemerkungen zu Cotyledon L."Jahrbuch der Deutschen Kakteen-Gesellschaft in der Deutschen Gesellschaft für Gartenkultur. Deutschen Kakteen-Gesellschaft: 94.
von Poellnitz, Karl (1937). "Beiträge zur Kenntnis der Gattung Cotyledon L.". Repertorium Novarum Specierum Regni Vegetabilis. 42 (1–10): 15–42. doi:10.1002/fedr.19370420107.
Botha, C.J.; Penrith, M.-L. (October 2008). "Poisonous plants of veterinary and human importance in southern Africa". Journal of Ethnopharmacology. 119 (3): 549–558. doi:10.1016/j.jep.2008.07.022. PMID18706990.
Botha, C.J.; Penrith, M.-L. (October 2008). "Poisonous plants of veterinary and human importance in southern Africa". Journal of Ethnopharmacology. 119 (3): 549–558. doi:10.1016/j.jep.2008.07.022. PMID18706990.
Smith, Gideon F.; Figueiredo, Estrela; van Wyk, Abraham E. (2019-01-01). "9: Biocultural Significance and Toxicity". In Smith, Gideon F.; Figueiredo, Estrela; van Wyk, Abraham E. (eds.). Kalanchoe (Crassulaceae) in Southern Africa. Academic Press. pp. 105–110. ISBN978-0-12-814007-9. Retrieved 2020-05-28.