HASSAN MAHMOOD, A.; اکرم; AHMED MOHAMED, A.; علاء. Investigation of solvability condition for sixth-order boundary value problem. Journal of Education and Science (JES), [S. l.], v. 25, n. 2, p. 70–75, 2012. DOI: 10.33899/edusj.2012.59157. Disponível em: https://rjps.uomosul.edu.iq/index.php/edusj/article/view/17857. Acesso em: 4 aug. 2025.