Tran, P., Nguyen, P., Pham, Q. and Tong, D. 2011. SYNTHESIS OF NOVEL URSOLIC ACID DERIVATIVES. VNUHCM Journal of Science and Technology Development. 14, 3 (Sep. 2011), 49-53. DOI:https://doi.org/https://doi.org/10.32508/stdj.v14i3.1963.