Marpomari Mahulae, Porman Juanda. “DESKRIPSI PERMASALAHAN UPAYA PENGEMBANGAN PARIWISATA BERKELANJUTAN DI DANAU TOBA SUMATERA UTARA(PROBLEM DESCRIPTION OF SUSTAINABLE TOURISM DEVELOPMENT EFFORT ON TOBA LAKE NORTH SUMATERA)”. Inovasi 16, no. 1 (May 23, 2019): 11–20. Accessed June 15, 2025. http://jurnal.bappelitbang.sumutprov.go.id/index.php/inovasi/article/view/130.