Yingqian Wang, Lingji Xu. Improper Choosability of Planar Graphs without 4-Cycles. SIAM J. Discrete Math., 27(4):2029-2037, 2013. [doi]
@article{WangX13-17,
title = {Improper Choosability of Planar Graphs without 4-Cycles},
author = {Yingqian Wang and Lingji Xu},
year = {2013},
doi = {10.1137/120885140},
url = {http://dx.doi.org/10.1137/120885140},
researchr = {https://researchr.org/publication/WangX13-17},
cites = {0},
citedby = {0},
journal = {SIAM J. Discrete Math.},
volume = {27},
number = {4},
pages = {2029-2037},
}