“Incremental Unknowns for the Heat Equation with Time-Dependent Coefficients: Semi-Implicit $\theta$-Schemes and Their Stability” (2007) Journal of Computational Mathematics, 25(5), pp. 573–582. Available at: https://www.global-sci.com/index.php/JCM/article/view/11850 (Accessed: 6 December 2025).