D. Yorike, M. R. Kurniawan, and M. Syafaat, “Analysis of D-Dimer Level and Prothombin Time (PT) Activated Prothombin Thromboplastin (APTT) on Heparin Administration to COVID-19 Patients”, IJMLST, vol. 4, no. 1, pp. 91–98, Apr. 2022.