Abel, Jennifer, Blake Allen, Strang Burton, Misuzu Kazama, Bosung Kim, Masaki Noguchi, Asami Tsuda, Noriko Yamane, and Bryan Gick. 2015. “Ultrasound-Enhanced Multimodal Approaches to Pronunciation Teaching and Learning”. Canadian Acoustics 43 (3). https://jcaa.caa-aca.ca/index.php/jcaa/article/view/2805.