Lev, Stark & Chang (2012), citing the same source, give these instead as [ɨ], [ɨ̃] and [ɨː]. Lev, Michael; Stark, Tammy; Chang, Will (2012). "Phonological inventory of Achuar-Shiwiar". The South American Phonological Inventory Database (version 1.1.3 ed.). Berkeley: University of California: Survey of California and Other Indian Languages Digital Resource.
Crevels, M. (2012). "Language endangerment in South America: The clock is ticking". In Campbell, L.; Grondona, V. (eds.). The Indigenous Languages of South America. Berlin: De Gruyter Mouton. pp. 167–234. doi:10.1515/9783110258035.167. ISBN978-3-11-025803-5.
King, K. A.; Haboud, M. (2002). "Language Planning and Policy in Ecuador". Current Issues in Language Planning. 3 (4): 359–424. doi:10.1080/14664200208668046.