TY - JOURNAL OF SHANDONG UNIVERSITY(NATURAL SCIENCE) A1 - ZHU Hai-yang, GU Yu, LÜ Xin-zhong T1 - New upper bound on the chromatic number of the square of a planar graph Y1 - 2016-02-16 JF - JOURNAL OF SHANDONG UNIVERSITY(NATURAL SCIENCE) JO - JOURNAL OF SHANDONG UNIVERSITY(NATURAL SCIENCE) SP - 94 EP - 101 VL - 51 IS - 2 UR - http://lxbwk.njournal.sdu.edu.cn N1 - 10.6040/j.issn.1671-9352.0.2014.594 ER -