Smith, J.F., Kresge, M.E., Möller, M. and 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), pp. 1–11. doi:10.1017/S0960428600004315.