Ang, Ju-Ying, Rhu-Yann Ho, Seng-Fah Tong, Fatimatuzzahra’ Abd. Aziz, and Guat-See Ooi. “The Prevalence of Online Natural Health Products Purchase: A Systematic Review”. Malaysian Journal of Medicine and Health Sciences 19, no. 2 (March 31, 2023): 250–258. Accessed November 9, 2025. http://mjmhsojs.upm.edu.my/index.php/mjmhs/article/view/398.