Mochammad Tutuk Safirin, et al. “Mental Workload Analysis of Workers Using the Swedish Occupational Fatigue Index (SOFI) Method at A Job Shop, Sheet Metal, And Pipe Metal Manufacturing Company in Surabaya”. Technium: Romanian Journal of Applied Sciences and Technology, vol. 16, no. 1, Oct. 2023, pp. 411-6, doi:10.47577/technium.v16i.10020.