Chan, Tsz Lung. “Contractible Edges in 2-Connected Locally Finite Graphs”. The Electronic Journal of Combinatorics 22, no. 2 (June 15, 2015): #P2.47. Accessed May 2, 2026. https://www.combinatorics.org/ojs/index.php/eljc/article/view/v22i2p47.