Thammarong, W., C. Maknoi, and P. Panyadee. “Heterostemma Succosum (Apocynaceae), a New Record for Laos”. Thai Forest Bulletin (Botany), vol. 47, no. 2, Oct. 2019, pp. 187-9, doi:10.20531/tfb.2019.47.2.09.