N. Nazar, J. J. Clarkson, D. Goyder, E. Kaky, T. Mahmood, and M. W. Chase, “Phylogenetic relationships in Apocynaceae based on nuclear PHYA and plastid trnL-F sequences, with a focus on tribal relationships”, Caryologia, vol. 72, no. 1, pp. 55–81, May 2019.