et. al., Gratia S. Sitorus ,. “Socio-Economic Life Cycle Assessment of Silangit Airport in Lake Toba Area”. Turkish Journal of Computer and Mathematics Education (TURCOMAT) 12, no. 8 (April 20, 2021): 3117–3124. Accessed November 7, 2025. https://www.turcomat.org/index.php/turkbilmat/article/view/4153.