Elchaira, Nadya, and Tengku Syarfina. “An Analysis of Formant Frequency of Indonesia Vowels By Bataknese and Javanese Speakers”. Linguistic, English Education and Art (LEEA) Journal 8, no. 1 (December 31, 2024): 143–154. Accessed April 4, 2025. https://journal.ipm2kpe.or.id/index.php/LEEA/article/view/10347.