1. On small faces in 4-critical graphs;Abbott;Ars Combin.,1991
2. Chromatic connected vertices in planar graphs;Aksenov;Diskretn. Analiz.,1977
3. On extending 3-colorability from two vertices in a planar triangle-free graph;Aksenov;Diskretn. Anal. Issled. Oper.,2002
4. On extending 3-colorability from a 6-face to a planar triangle-free graph;Aksenov;Diskretn. Anal. Issled. Oper.,2003
5. Extending 3-colorability from a 7-face to a planar triangle-free graph;Aksenov;Sib. Elektron. Mat. Izv.,2004