I.  Hedberg, Kelbessa, E., Edwards, S., Demissew, S., ? Persson, E., ??????, "Flora of Ethiopia and Eritrea, Volume 5: Gentianaceae to Cyclocheilaceae", Addis Ababa, Ethiopia: The National Herbarium, Addis Ababa, Ethiopia, and Department of Systematic Botany, Uppsala, SwedenAddis Ababa, Ethiopia: The National Herbarium, Addis Ababa, Ethiopia, and Department of Systematic Botany, Uppsala, Sweden, 2006.