Kaufman, Allison B.; Colbert-White, Erin N.; Burgess, Curt (2013). "Higher-order semantic structures in an African Grey parrot's vocalizations: evidence from the hyperspace analog to language (HAL) model". Animal Cognition. 16 (1): 789–801. doi:10.1007/s10071-013-0613-3. PMID23417559. S2CID11359605.
Colbert-White, Erin; Hall, Hannah; Fragazsy, Dorothy (2016). "Variations in an African Grey parrot's speech patterns following ignored and denied requests". Animal Cognition. 19 (3): 459–469. doi:10.1007/s10071-015-0946-1. PMID26700613. S2CID2201504.
Snyder, Peter J.; Harris, Lauren Julius (11 November 1996). "Lexicon size and its relation to foot preference in the African Grey parrot "Psittacus erithacus"". Neuropsychologia. 35 (6): 919–926. doi:10.1016/s0028-3932(97)00010-9. PMID9204496. S2CID7067828.
"Nonnatives – Gray Parrot". myfwc.com. Florida Fish and Wildlife Conservation Commission. Archived from the original on 28 June 2018. Retrieved 5 June 2024.
Kaufman, Allison B.; Colbert-White, Erin N.; Burgess, Curt (2013). "Higher-order semantic structures in an African Grey parrot's vocalizations: evidence from the hyperspace analog to language (HAL) model". Animal Cognition. 16 (1): 789–801. doi:10.1007/s10071-013-0613-3. PMID23417559. S2CID11359605.
Colbert-White, Erin; Hall, Hannah; Fragazsy, Dorothy (2016). "Variations in an African Grey parrot's speech patterns following ignored and denied requests". Animal Cognition. 19 (3): 459–469. doi:10.1007/s10071-015-0946-1. PMID26700613. S2CID2201504.
Snyder, Peter J.; Harris, Lauren Julius (11 November 1996). "Lexicon size and its relation to foot preference in the African Grey parrot "Psittacus erithacus"". Neuropsychologia. 35 (6): 919–926. doi:10.1016/s0028-3932(97)00010-9. PMID9204496. S2CID7067828.
Kaufman, Allison B.; Colbert-White, Erin N.; Burgess, Curt (2013). "Higher-order semantic structures in an African Grey parrot's vocalizations: evidence from the hyperspace analog to language (HAL) model". Animal Cognition. 16 (1): 789–801. doi:10.1007/s10071-013-0613-3. PMID23417559. S2CID11359605.
Colbert-White, Erin; Hall, Hannah; Fragazsy, Dorothy (2016). "Variations in an African Grey parrot's speech patterns following ignored and denied requests". Animal Cognition. 19 (3): 459–469. doi:10.1007/s10071-015-0946-1. PMID26700613. S2CID2201504.
Snyder, Peter J.; Harris, Lauren Julius (11 November 1996). "Lexicon size and its relation to foot preference in the African Grey parrot "Psittacus erithacus"". Neuropsychologia. 35 (6): 919–926. doi:10.1016/s0028-3932(97)00010-9. PMID9204496. S2CID7067828.
"Nonnatives – Gray Parrot". myfwc.com. Florida Fish and Wildlife Conservation Commission. Archived from the original on 28 June 2018. Retrieved 5 June 2024.