M SIANTURI, Novdin et al. Assessment of Environmental Management in Lake Toba, Samosir Regency, North Sumatera Province, Indonesia. International Journal of Engineering and Technology, [S. l.], v. 7, n. 3.14, p. 337–343, 2018. DOI: 10.14419/ijet.v7i3.14.18815. Disponível em: https://sciencepubco.com/index.php/IJET/article/view/18815.. Acesso em: 12 apr. 2025.