Harahap, A. S., Mulyono, H., Hasibuan, A. L., & Siregar, T. South batak tradition for the settlement of environmental disputes: A tumbaga holing letter model. 12, 1811-1825. https://doi.org/10.14505/jemt.v12.7(55).07
A.S. Harahap H. Mulyono A.L. Hasibuan T. SiregarCommunity of Batak Environmental protection Surat Tumbaga Holing