1. Every map is four colorable: part 1, discharging;Appel;Illinois J. Math.,1977
2. Every map is four colorable: part 2, reducibility;Appel;Illinois J. Math.,1977
3. 2-distance coloring of sparse graphs;Bonamy;J. Graph Theory,2014
4. On the total coloring of planar graphs;Borodin;J. Reine Angew. Math.,1989
5. Sufficient conditions for the 2-distance (Δ+1)-colorability of plane graphs;Borodin;Sib. Electron. Math. Reports,2004