1. Hirsch, K. F. & Quinn, B. Eggs and eggshell fragments from the Upper Cretaceous Two Medicine Formation of Montana. J. Vertebr. Paleontol. 10, 491–511 (1990).
2. Mikhailov, K. E. Fossil and recent eggshell in amniotic vertebrates: Fine structure, comparative morphology and classification. Spec. Pap. Palaeontol. 56 (1997).
3. Zelenitsky, D. K., Modesto, S. & Currie, P. J. Bird-like characteristics of troodontid theropod eggshell. Cret. Res. 23, 297–305 (2002).
4. Grellet-Tinner, G. & Chiappe, L. M. Dinosaur eggs and nesting: Implications for understanding the origin of birds. In Feathered dragons: studies on the transition from dinosaurs to birds (eds Currie, P. J., Koppelhus, E. B., Shugar, M. A. & Wright, J. L.) 185–214, (Indiana University Press, 2004).
5. Varricchio, D. J. & Jackson, F. D. A phylogenetic assessment of prismatic dinosaur eggs from the Cretaceous Two Medicine Formation of Montana. J. Vertebr. Paleontol. 24, 931–937 (2004).