S. M. Chuiko, “Least-squares method in the theory of ill-posed linear boundary-value problems with pulse action”, Ukr. Mat. Zhurn., vol. 62, no. 5, pp. 690–697, May 2010, Accessed: Feb. 16, 2026. [Online]. Available: https://umj.imath.kiev.ua/index.php/umj/article/view/2899