Billy, Billy Fernanda Kurniawan, Juita Triana, and Andrian Nuriza Johan. “The Analysis of Difficulties in Pronouncing English Vowels (Monophthongs) in Singing English Song”. Scripta : English Department Journal 9, no. 1 (August 21, 2022): 35-43. Accessed November 15, 2024. https://ebook.umpwr.ac.id/index.php/scripta/article/view/1455.