中国科学院数学与系统科学研究院期刊网
AMS
A Structural Theorem on Embedded Graphs and Its Application to Colorings
Bao Gang XU, Xiao Xu LU
Acta Mathematica Sinica . 2009, (1): 47 -50 .  DOI: 10.1007/s10114-008-7011-9