Authors Year Title
Ruan & Zhou 1987 Carboniferous cephalopods in Ningxia Hui Autonomous Region. [In Chinese, with Engl. summary].
Namurian Strata and Fossils of Ningxia, China: 55-177, 78 text-figs., 15 pls., Nanjing.
Yang, Zheng & Liu 1983 Carboniferous ammonoid zones from Zhongning and Zhongwei, Ningxia Region, China.
Earth Science - Journal of Wuhan College of Geology, 20 (2): 9-23, tab.1-3, pl.1; Wuhan.