SETYANINGSIH, Kuntum Palupi; WIJAYANTO, Agus; SUPARNO, Suparno. English Vowels and Diphthongs Problems of Sundanese Learners. ELS Journal on Interdisciplinary Studies in Humanities, [S. l.], v. 2, n. 4, p. 571–581, 2019. DOI: 10.34050/els-jish.v2i4.8413. Disponível em: https://journal.unhas.ac.id/index.php/jish/article/view/8413. Acesso em: 28 feb. 2026.