Damanik SE, Rozalina R, Nurrachmania M. Influence of sipinsur ecotourism area business opportunity on regional development in humbang hasundutan regency. ijbem [Internet]. 2021Apr.7 [cited 2024Jul.16];4(1):130-4. Available from: https://sloap.org/journal/index.php/ijbem/article/view/1336