Morrison, Geoffrey Stewart. “Perception of Synthetic Vowels by Monolingual Canadian-English, Mexican-Spanish, and Peninsular-Spanish Listeners”. Canadian Acoustics 36, no. 4 (December 1, 2008): 17-23. Accessed May 12, 2021. https://jcaa.caa-aca.ca/index.php/jcaa/article/view/2100.