Mudstones in the Upper Permian coal-bearing series in eastern Yunnan and western Guizhou： Clay minerals composition and their environmental significance
Luo Zhong, Shao Longyi, Yao Guanghua, Deng Guangming, Wang Hao, Han Jun
JOURNAL OF PALAEOGEOGRAPHY . 2008, (3): 297 -304 .  DOI: 10.7605/gdlxb.2008.03.009