J. S. Hollingsworth. 1999. The problematical base of the Montezuman Stages: should the Laurentian Fallotaspidids be in a non-trilobite series. Laurentia 99: V field conference of the Cambrian Stage Subdivision Working Group, International Subcommission on Cambrian Stratigraphy 5-9 [M. Patzkowsky/P. Borkow]