A high-pyrite semianthracite of Late Permian age in the Songzao Coalfield, southwestern China: Mineralogical and geochemical relations with underlying mafic tuffs - Dai, S.; Wang, X.; Chen, W.; Li, D.; Chou, C.; Zhou, Y.; Zhu, Chen; Li, H.; Zhu, Xudong; Xing, Y.; Zhang, W.; Zou, J. (International Journal of Coal Geology, 2010)