The density of the set of unsolvable Cauchy problems in the set of all Cauchy problems for an infinite-dimensional Banach space. Neliniini Kolyvannya, [S. l.], v. 5, n. 1, p. 86–89, 2002. Disponível em: https://twinhead.imath.kiev.ua/index.php/nosc/article/view/203. Acesso em: 22 jan. 2026.