Simanjuntak, M., and A. G. Malau. “Level of Competency Needs Assessment Based on Permenhub No. PM 7 of 2018 Concerning the Master Plan for Skkni Development Transportation Sector”. International Review of Management and Marketing, vol. 9, no. 5, Sept. 2019, pp. 87-94, https://www.econjournals.com/index.php/irmm/article/view/8593.