Novawati Siregar, Ruth Riah Ate Tarigan, & Feby Milanie. (2025). Model for Optimizing the Development of Aek Sijorni Natural Bath Tourism in South Tapanuli Regency. International Journal of Mechanical, Electrical and Civil Engineering, 2(3), 216–230. https://doi.org/10.61132/ijmecie.v2i3.327