Smith, G. F. “The ‘woody clade’ in Kalanchoe: Reinstatement and Amendment of K. Subg. Calophygia (Crassulaceae Subfam. Kalanchooideae) Published by Bernard Marie Descoings in 2006”. Phytotaxa, vol. 616, no. 2, Sept. 2023, pp. 113-27, doi:10.11646/phytotaxa.616.2.1.