Robert Tua Siregar, Hery Pandapotan Silitonga. “Development of Wastewater Treatment (Ipal) Communal Plant in Village Pardomuan Nauli in the District Laguboti District Toba Samosir With the Power of Community Participation”. International Journal of Advanced Science and Technology 29, no. 06 (June 1, 2020): 7609-7617. Accessed May 2, 2024. http://sersc.org/journals/index.php/IJAST/article/view/25116.