PUTRA, G. A.; MULYANTINI, S.; ARIEFTIARA, D. Business diversification of coal mining companies as a strategy facing coal price volatility: The effect on company performance and share prices. International Journal of Business Ecosystem & Strategy (2687-2293), [S. l.], v. 3, n. 4, p. 38–50, 2021. DOI: 10.36096/ijbes.v3i4.299. Disponível em: https://bussecon.com/ojs/index.php/ijbes/article/view/299. Acesso em: 25 sep. 2025.