Sharp Error Estimate of Variable Time-Step Imex BDF2 Scheme for Parabolic Integro-Differential Equations with Initial Singularity Arising in Finance. JCM [Internet]. 2025 Sep. 28 [cited 2025 Dec. 6];43(5):1118-40. Available from: https://www.global-sci.com/index.php/JCM/article/view/22795