1. On small faces in 4-critical graphs;Abbott;Ars Combin.,1991
2. Coloring powers of planar graphs;Agnarsson;SIAM J. Discrete Math.,2003
3. The extension of a 3-coloring on planar graphs;Aksenov;Diskret. Analiz,1974
4. Chromatic connected vertices in planar graphs;Aksenov;Diskret. Analiz,1977
5. On the continuation of a 3-coloring from two vertices in a plane graph without 3-cycles;Aksenov;Diskretn. Anal. Issled. Oper.,2002