См. Irene Maxine Pepperberg, The Alex Studies: Cognitive and Communicative Abilities of Grey Parrots (Cambridge, MA: Harvard University Press, 2000); Nathan Emery and Nicola Clayton, «The Mentality of Crows: Convergent Evolution of Intelligence in Corvids and Apes», Science, 306 (2004): 1903–1907; Alex Taylor, «Corvid Cognition», WIREs Cognitive Science, 5, no. 3 (2014): 361–372.
