Ibrahim SE-S. On the Product of Self-Adjoint Sturm-Liouville Differential Operators in Direct Sum Spaces. Jour. Inform. Math. Sci. [Internet]. 2012 Apr. 1 [cited 2025 Oct. 26];4(1):93-109. Available from: https://www.journals.rgnpublications.com/index.php/jims/article/view/71