Sharp Error Estimate of Variable Time-Step Imex BDF2 Scheme for Parabolic Integro-Differential Equations with Initial Singularity Arising in Finance. JCM [Internet]. 2025 Sept. 28 [cited 2026 Mar. 17];43(5):1118-40. Available from: https://staging.gsp.tricubic.dev/JCM/article/view/22795