Hall, Kathleen Currie, Hanna Smith, Kevin McMullin, Blake Allen, and Noriko Yamane. 2017. “Using Optical Flow Analysis on Ultrasound of the Tongue to Examine Phonological Relationships”. Canadian Acoustics 45 (1):15-24. https://jcaa.caa-aca.ca/index.php/jcaa/article/view/2740.