Sirik, S. V. “Estimation of the Accuracy of Finite-Element Petrov–Galerkin Method in Integrating the One-Dimensional Stationary Convection-Diffusion-Reaction Equation”.
Ukrains’kyi Matematychnyi Zhurnal 67, no. 7 (July 25, 2015): 937–961. Accessed April 7, 2025.
https://umj.imath.kiev.ua/index.php/umj/article/view/2034.