Varricchio, David J. (2002). "A new bird from the Upper Cretaceous Two Medicine Formation of Montana". Canadian Journal of Earth Sciences. 39 (1): 19–26. Bibcode:2002CaJES..39...19V. doi:10.1139/e01-057.
Varricchio, David J. (2002). "A new bird from the Upper Cretaceous Two Medicine Formation of Montana". Canadian Journal of Earth Sciences. 39 (1): 19–26. Bibcode:2002CaJES..39...19V. doi:10.1139/e01-057.