Carpenter, K. Vertebrate Biostratigraphy of the Smoky Hill Chalk (Niobrara Formation) and the Sharon Springs Member (Pierre Shale). Harries, P. J. (编). High-resolution Approaches in Stratigraphic Paleontology. Topics in Geobiology 21. Dordrecht: Kluwer Academic Publishers. 2008: 421–437. ISBN 978-1-4020-9053-0. doi:10.1007/978-1-4020-9053-0.
