MEI Shi-long,1991.Middle and Late Cambrian conodont and trilobite biostratigraphy in Wanxian,Hebei.Unpublished Ph.D thes武桂春,2003.鲁西地区晚寒武世牙形石.北京大学博士研究生学位论文.
The new framework, comprising a pre-trilobite series and three trilobite-dominated series, reflects the major evolutiona新的划分方案包括1个“前三叶虫统”和3个“三叶虫优势统”，反映了寒武纪生命发展的主要阶段。