“Sharp Upper Estimates for the First Eigenvalue of a Jacobi Type Operator”, Extr. Math., vol. 31, no. 1, p. 69–88, Jun. 2016, Accessed: Dec. 22, 2024. [Online]. Available: https://revista-em.unex.es/index.php/EM/article/view/2605-5686.31.1.69