Halian, Wahana, Bonar M. Sinaga, and Tanti Novianti. “Factors Affecting Profitability of Construction Company Sub-Sector”. Indonesian Journal of Business and Entrepreneurship (IJBE) 6, no. 2 (May 30, 2020): 118. Accessed March 3, 2021. http://jma.journal.ipb.ac.id/index.php/ijbe/article/view/31008.