Ngibad, K.; Yusmiati, S. N. H.; Santoso, S. D.; Inayah, F.; Faizi, R. D. N. In Vitro Antioxidant Activity, Flavonoid and Phenolic Contents of 70% Methanol Extract from Purple and Yellow Passion Fruit Peel. Indo. J. Chem. Env. 2023, 6, 54-62.