Dalfó, C., M. A. Fiol, and E. Garriga. “A Differential Approach for Bounding the Index of Graphs under Perturbations”. The Electronic Journal of Combinatorics 18, no. 1 (September 2, 2011): P172. Accessed April 3, 2026. https://www.combinatorics.org/ojs/index.php/eljc/article/view/v18i1p172.