Siregar, Enni Sari, Nurintan Siregar, and Pahrurrozi Pane. “Environmental Investment on Economic Growth and Sustainable Development: A Case Study of North Sumatra”. Husnayain Business Review 6, no. 2 (October 22, 2026): 306–315. Accessed October 25, 2026. https://journal.adpebi.com/index.php/hbr/article/view/1784.