Sitepu VB, Soma AM. 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 [Internet]. 2025 Jul. 21 [cited 2025 Nov. 4];2(1):1-26. Available from: https://goodwoodpub.com/index.php/JoMAPS/article/view/3209