Grabau, A. W. (1922). Ordovician fossils of north China. Geological Survey of China.
芝加哥风格引文Grabau, Amadeus W. Ordovician Fossils of North China. Peking: Geological Survey of China, 1922.
MLA引文Grabau, Amadeus W. Ordovician Fossils of North China. Geological Survey of China, 1922.
警告：这些引文格式不一定是100％准确.