W. Phaik-Ean, N. Lee Abdullah, R. Idrus, and P. Keikhosrokiani, “Real Time Productivity Monitoring System for Small and Medium Size Manufacturing Industry”, IJET, vol. 7, no. 4.31, pp. 128–134, Dec. 2018, doi: 10.14419/ijet.v7i4.31.23355.