Antioxidant Activity of Ethanolic Extract and Various Fractions from Green Tea (Camellia sinensis L.) Leaves, Indarti, Karmika, Apriani Elsa Fitria, Wibowo Agung Eru, and Simanjuntak Partomuan , Pharmacognosy Journal, July 2019, Volume 11, Issue 4, p.771-776, (2019)