SITEPU, V. B.; SOMA, A. M. Comparison of black scholes and garch models using collar strategy as a hedging efforts in the telecommunication industry (Telkomsel, XL, Indosat). Journal of Multidisciplinary Academic and Practice Studies, Indonesia, v. 2, n. 1, p. 1–26, 2024. DOI: 10.35912/jomaps.v3i3.3209. Disponível em: https://goodwoodpub.com/index.php/jomaps/article/view/3209. Acesso em: 24 apr. 2026.