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, [S. l.], v. 3, n. 3, p. 651–675, 2025. DOI: 10.35912/jomaps.v3i3.3209. Disponível em: https://goodwoodpub.com/index.php/JoMAPS/article/view/3209. Acesso em: 1 aug. 2025.