Kamaruddin, Harni Sartika, et al. “Determination of Polyphenol Content in Sawo Fruit (Manilkara Zapota) Based on Geographical Location ”. Journal of Tropical Pharmacy and Chemistry, vol. 5, no. 3, June 2021, pp. 239-44, doi:10.25026/jtpc.v5i3.300.