Munthe, I. R., B. H. Rambe, R. Pane, D. Irmayani, and M. Nasution. “UML Modeling and Black Box Testing Methods in the School Payment Information System”. Jurnal Mantik, vol. 4, no. 3, Nov. 2020, pp. 1634-40, doi:10.35335/mantik.Vol4.2020.969.pp1634-1640.