M. H. Ester Kalangi, I. Kristiawati, and R. A. Ega Kusuma, “Impact of Work Skills, Performance, and Maintenance on Productivity: A Study on Head Truck Operators in PT. Terminal Petikemas Surabaya”, acopen, vol. 8, no. 1, p. 10.21070/acopen.8.2023.6664, Jul. 2023.