Yu, K., and D.G. Jamieson. “Training of the English /r/ and /l/ Speech Contrasts in Korean Listeners”. Canadian Acoustics 21, no. 3 (September 1, 1993): 107–108. Accessed April 20, 2024. https://jcaa.caa-aca.ca/index.php/jcaa/article/view/797.