Lenore J. Cowen, Robert Cowen, D. R. Woodall. Defective colorings of graphs in surfaces: Partitions into subgraphs of bounded valency. Journal of Graph Theory, 10(2):187-195, 1986. [doi]
@article{CowenCW86,
title = {Defective colorings of graphs in surfaces: Partitions into subgraphs of bounded valency},
author = {Lenore J. Cowen and Robert Cowen and D. R. Woodall},
year = {1986},
doi = {10.1002/jgt.3190100207},
url = {http://dx.doi.org/10.1002/jgt.3190100207},
researchr = {https://researchr.org/publication/CowenCW86},
cites = {0},
citedby = {0},
journal = {Journal of Graph Theory},
volume = {10},
number = {2},
pages = {187-195},
}