^Hackett, S.J.; et al. A Phylogenomic Study of Birds Reveals Their Evolutionary History. Science. 2008, 320 (5884): 1763–8. PMID 18583609. doi:10.1126/science.1157704.
^Naish, D. (2012). "Birds." Pp. 379-423 in Brett-Surman, M.K., Holtz, T.R., and Farlow, J. O. (eds.), The Complete Dinosaur (Second Edition). Indiana University Press (Bloomington & Indianapolis).
^ 5.05.1Kimball, R.T. et al. (2013) Identifying localized biases in large datasets: A case study using the Avian Tree of Life. Mol Phylogenet Evol. doi:10.1016/j.ympev.2013.05.029