Nguyen TTT, Nguyen TNH, Tu VH, et al. INVESTIGATION OF CHEMICAL CONSTITUENTS AND ANTI PROPIONIBACTERIUM ACNES ACTIVITY OF THE LICHEN USNEA UNDULATA STIRTON (PARMELIACEAE). CTJUMP. 2026;(36):206-212. Accessed August 26, 2026. https://tapchi.ctump.edu.vn/index.php/ctump/article/view/906