The Hell Creek Formation and the Cretaceous-Tertiary boundary in the northern Great
Plains : an integrated continental record of the end of the Cretaceous / Edited by
Joseph H. Hartman, Kirk R. Johnson, and Douglas J. Nichols. Geological Society of
America; 2002
Travels with trilobites : adventures in the Paleozoic / Andy Secher, 2022
Information trouvée : Directeur du Smithsonian's National Museum of Natural History