Cauvi, Justine, Ruoying Li, and Sabine Storandt. “Exact and Approximate Hierarchical Hub Labeling”. Journal of Graph Algorithms and Applications 29, no. 2 (May 20, 2025): 103–126. Accessed June 18, 2025. https://jgaa-v4.cs.brown.edu/index.php/jgaa/article/view/3041.