Cotyledon

• van Jaarsveld, E. & Koutnik, D. 2004. Cotyledon and Tylecodon. Umdaus Press, Pretoria.

Crassula

• Rowley, G. 2003. Crassula, A Growers Guide. Cactus& Co., Italy.

• Tolken, H.R. 1985. Flora of Southern Africa, Volume 14, Crassulaceae. Botanical Research Institute, Department of Agriculture and Water Supply, Pretoria.

Tylecodon

• van Jaarsveld, E. & Koutnik, D. 2004. Cotyledon and Tylecodon. Umdaus Press. Pretoria.