Sonia Sabilla, Masriyanti Nasution, and Yani Lubis. “The Concept Of Vowel Sounds To Students Ability In Phonology”. Jurnal Pendidikan dan Sastra Inggris 3, no. 2 (August 30, 2023): 179–187. Accessed May 19, 2024. https://ejurnal.politeknikpratama.ac.id/index.php/JUPENSI/article/view/2024.