1. N. S. Bakhvalov, N. P. Zhidkov, and G. M. Kobel’kov, Numerical Methods (Nauka, Moscow, 1987) [in Russian].
2. A. I. Zadorin, “Method of interpolation for a boundary layer problem,” Sib. Zh. Vychisl. Mat. 10 (3), 267–275 (2007).
3. A. I. Zadorin and N. A. Zadorin, “Interpolation formula for functions with a boundary layer component and its application to derivatives calculation,” Sib. Electron. Math. Rep. 9, 445–455 (2012).
4. R. B. Kellogg and A. Tsan, “Analysis of some difference approximations for a singular perturbation problem without turning points,” Math. Comput. 32, 1025–1039 (1978).
5. A. I. Zadorin and N. A. Zadorin, “Non-polynomial interpolation of functions with large gradients and its application,” Comput. Math. Math. Phys. 61 (2), 167–176 (2021).