Research on support difficulty classification for roadways with thick mudstone roof and its application
MA Zhenqian, JIANG Yaodong, WU Guiyi, ZUO Yujun, GAO Lin
China Safety Science Journal . 2017, (11): 121 -125 .  DOI: 10.16265/j.cnki.issn1003-3033.2017.11.021