Syamsu Nur, Andi Nur Aisyah, Alfat Fadri, Sharfianty, Amriani Sapra and Fitriyanti Jumaetri Sami 2021. Comparative study of catechin levels from green tea, oolong tea and black tea product with various treatments. GSC Biological and Pharmaceutical Sciences. 14, 1 (Jan. 2021), 01–010. DOI:https://doi.org/10.30574/gscbps.2021.14.1.0416.