ILIEV, H. On the non-integrability of a Hamiltonian system resulting from a problem for elastic string. Ann. Sofia Univ. Fac. Math. and Inf., [S. l.], v. 88, p. 57–69, 1996. Disponível em: https://ftl5.uni-sofia.bg/index.php/fmi/article/view/379. Acesso em: 4 dec. 2024.