@inproceedings{DikKowKur-WG-02,
   title = {A new 3-color criterion for planar graphs},
   author = {Krzysztof Diks and {\L}ukasz Kowalik and Maciej Kurowski},
   booktitle = {Proc. 28th Int. Worksh. Graph-Theoretic Concepts in Computer
Science (WG 2002)},
   number = {2573},
   editor = {Ludek Kucera},
   series = {Lecture Notes in Computer Science},
   publisher = {Springer-Verlag},
   pages = {138--149},
   year = {2002}}