Peleg, David, and Alejandro A. Schäffer. “Graph Spanners”. Journal of Graph Theory, vol. 13, no. 1, 1989, pp. 99-116, https://doi.org/10.1002/jgt.3190130114.
Peleg, D., & Schäffer, A. A. (1989). Graph spanners. Journal of Graph Theory, 13(1), 99-116. https://doi.org/10.1002/jgt.3190130114