Srisombat, Nattawut, Sorawit Bapia, Siriluk Ratanabunyong, Kiattawee Choowongkomon, Srunya Vajrodaya, and Sutsawat Duangsrisai. “Isolation of betulinic acid and antioxidant and anti-HIV-1 reverse transcriptase activity of Cratoxylum formosum subsp. pruniflorum (Kurz) Gogelein extract”. Agriculture and Natural Resources 53, no. 6 (December 31, 2019): 674–680. accessed December 8, 2025. https://li01.tci-thaijo.org/index.php/anres/article/view/240022.