1. On the Cambrian faunas of North America. Preliminary studies Author/Creator: Walcott, Charles D. 1850-1927. (Charles Doolittle) Publication/Creation: Washington : Govt. Print. Off, 1884 Resource Type: Book Is Part Of: U.S. Geological Survey bulletin, no. 8-14. Access & Availability: Loading
2. Ontogeny, intraspecific variation, and systematics of the Late Cambrian trilobite Dikelocephalus Author/Creator: Hughes, Nigel C. Publication/Creation: Washington, D.C. : Smithsonian Institution Press, 1994 Resource Type: Book Access & Availability: Loading