Petrified Forest National Park
High-resolution U–Pb ages from the Upper Triassic Chinle Formation (New Mexico, USA) support a diachronous rise of dinosaurs
2011 · Randall B. Irmis, Roland Mundil, et al. · Earth and Planetary Science Letters
Early ornithischian dinosaurs: the Triassic record
2006 · Randall B. Irmis, William G. Parker, et al. · Historical Biology
A critical re‐evaluation of the Late Triassic dinosaur taxa of North America
2007 · Sterling J. Nesbitt, Randall B. Irmis, et al. · Journal of Systematic Palaeontology