@article{10_21136_CMJ_2019_0558_17,
     author = {Chu, Yanan and Sun, Lei and Yue, Jun},
     title = {Note on improper coloring of $1$-planar graphs},
     journal = {Czechoslovak Mathematical Journal},
     pages = {955--968},
     publisher = {mathdoc},
     volume = {69},
     number = {4},
     year = {2019},
     doi = {10.21136/CMJ.2019.0558-17},
     mrnumber = {4039612},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.21136/CMJ.2019.0558-17/}
}