Derrick, D., B. Gick, and I. Stavness. “Two Phonological Segments, One Motor Event: Evidence for Speech-Motor Disparity from English Flap Production”. Canadian Acoustics, vol. 38, no. 3, Sept. 2010, pp. 128-9, https://jcaa.caa-aca.ca/index.php/jcaa/article/view/2278.