IYASE, S. A. . On The Non-Resonant Oscillation Of A Fourth Order Periodic Boundary Value Problem With Delay. Journal of the Nigerian Mathematical Society, [S. l.], v. 32, n. 1-3, p. 217–227, 2021. Disponível em: https://ojs.ictp.it/jnms/index.php/jnms/article/view/695. Acesso em: 3 may. 2024.