Smith, J. F., Kresge, M. E., Möller, M., & Cronk, Q. C. B. (1998). A cladistic analysis of ndhF sequences from representative species of Saintpaulia and Streptocarpus subgenera Streptocarpus and Streptocarpella (Gesneriaceae). Edinburgh Journal of Botany, 55(1), 1-11. https://doi.org/10.1017/S0960428600004315