Rahmat, R., E. Mohamad, R. Jaafar, A. Saptari, N. Mohamad, D. Yuniawan, and T. Ito. “IMPROVING ELECTRONIC DOCUMENT CONTROL APPROVAL PROCESS THROUGH E-CERTIFICATION”. Journal of Advanced Manufacturing Technology (JAMT), vol. 13, no. 1, Aug. 2019, pp. 33-44, https://ojsdemo.utem.edu.my/jamt/article/view/5250.