Autonomous boundary-value problem unsolvable with respect to the derivative. Neliniini Kolyvannya, [S. l.], v. 26, n. 4, p. 543–554, 2023. DOI: 10.3842/nosc.v26i4.1439. Disponível em: https://twinhead.imath.kiev.ua/index.php/nosc/article/view/1123. Acesso em: 21 jan. 2026.