Stability and boundedness results on certain nonlinear vector diferential equations of fourth order. Neliniini Kolyvannya, [S. l.], v. 9, n. 4, p. 548–563, 2006. Disponível em: https://twinhead.imath.kiev.ua/index.php/nosc/article/view/414. Acesso em: 21 jan. 2026.