Siallagan, Saskia, and Payerli Pasaribu. “Strategi Membangun Solidaritas Pada Persekutuan Remaja Naposobulung HKBP Air Bersih”. SAKOLA: Journal of Sains Cooperative Learning and Law, vol. 1, no. 2, Sept. 2024, pp. 271-8, doi:10.57235/sakola.v1i2.3271.