Siregar, Siddik, Eddy Irsan Siregar, and . . “Differentiation Strategy of Soes Construction Service in Indonesia: A Point of View of Project Managers”. International Journal of Engineering and Technology 7, no. 2.29 (May 22, 2018): 899–904. Accessed May 19, 2025. https://mail.sciencepubco.com/index.php/IJET/article/view/14279.