NAPITUPULU, M. F.; ANWAR , H. F.; LUBIS , Y. Error Pronouncing English Vowels. Jurnal Pendidikan Rafflesia, [S. l.], v. 1, n. 2, p. 27–, 2023. DOI: 10.70963/jpr.v1i2.37. Disponível em: https://jurnal.geinrafflesia.com/index.php/JPR/article/view/37. Acesso em: 1 jun. 2026.