Sinaga EK, Silalahi NN, Eppang BM. Sustainable tour operator practices: A case study of PT Destination Asia. IJASTE [Internet]. 2025 Jun. 30 [cited 2026 Feb. 4];9(1):41-55. Available from: https://ojs2.pnb.ac.id/index.php/IJASTE/article/view/2515