Bigun, Y.I. and Filipchuk, M.P. (1998) “Numerical-analytic method for the investigation of multipoint boundary-value problems for systems of differential equations with transformed argument”, Ukrains’kyi Matematychnyi Zhurnal, 50(11), pp. 1581–1584. Available at: https://umj.imath.kiev.ua/index.php/umj/article/view/4815 (Accessed: 5 December 2025).