Souvannakhoummane, K., et al. “FLORA OF NAM KADING NATIONAL PROTECTED AREA VI: DIDYMOCARPUS MIDDLETONII (GESNERIACEAE), A NEW SPECIES FROM LIMESTONE”. Edinburgh Journal of Botany, vol. 76, no. 1, Nov. 2018, pp. 45-54, https://doi.org/10.1017/S0960428618000264.