Pasaribu, E. et al. 2018. Extraction and Characterization of Pepsin Enzyme from Tuna (Thunnus albacares) Gastric. Jurnal Pengolahan Hasil Perikanan Indonesia. 21, 3 (Dec. 2018), 486–496. DOI:https://doi.org/10.17844/jphpi.v21i3.24727.