1. Solution of Ringel's problem about vertex bound colouring of planar graphs and colouring of 1-planar graphs;Borodin;Metody Discret. Analiz.,1984
2. A new proof of the 6-color theorem;Borodin;J. Graph Theory,1995
3. Acyclic colouring of 1-planar graphs;Borodin;Discrete Anal. Oper. Res.,1999
4. Bemerkungen zu einen Sechsfarbenproblem von G. Ringel;Bodendiek;Abh. Math. Semin. Univ. Hamb.,1983
5. Approximation algorithms for independent sets in map graphs;Chen;J. Algorithms,2001