Bonnet, Édouard, C. Feghali, T. Nguyen, A. Scott, P. Seymour, S. Thomassé, and N. Trotignon. “Graphs Without a 3-Connected Subgraph Are 4-Colourable”. The Electronic Journal of Combinatorics, Vol. 32, no. 1, Feb. 2025, p. P1.26, doi:10.37236/13181.