de Souza, Isaac Costa (2010). "3"(PDF). A Phonological Description of "Pet Talk" in Arara (MA). SIL Brazil. Archived from the original(PDF) on 2013-10-12. Retrieved 2014-01-09.
Maddieson, Ian (2008), "Absence of Common Consonants", in Haspelmath, Martin; Dryer, Matthew S.; Gil, David; Comrie, Bernard (eds.), The World Atlas of Language Structures Online, Munich: Max Planck Digital Library
de Souza, Isaac Costa (2010). "3"(PDF). A Phonological Description of "Pet Talk" in Arara (MA). SIL Brazil. Archived from the original(PDF) on 2013-10-12. Retrieved 2014-01-09.
