References
For Aizopsis
Gontcharova, S.B., E.V. Artyukova, and A.A. Gontcharov. 2006. Phylogenetic relationships among members of the subfamily Sedoideae (Crassulaceae) inferred from the ITS region sequences of nuclear rDNA. Russian J. Gen. 42(6): 654-661. Google Scholar
Thiede, J., and U. Eggli. 2007. Crassulaceae. In Kubitzki, K., C. Bayer, and P.F. Stevens, eds. 2007. The families and genera of vascular plants. IX. Flowering plants – Eudicots – Berberidopsidales, Buxales, Crossosomatales, Fabales p.p., Geraniales, Gunnerales, Myrtales p.p., Proteales, Saxifragales, Vitales, Zygophyllales, Clusiaceae alliance, Passifloraceae alliance, Dilleniaceae, Huaceae, Picramniaceae, Sabiaceae. Springer, Berlin. 509 pp. Google Scholar