Rusmawaty, D., E. Limbong, I. Ahada, M. I. F. Hafizh, and A. N. Rahmatullah. “Unlocking Phonological Proficiency: Exploring Allophonic Variation Using ELSA Speak App in Early Semester EFL Students at Mulawarman University”. Indonesian Journal of EFL and Linguistics, Vol. 9, no. 2, Nov. 2024, pp. 337-48, doi:10.21462/ijefl.v9i2.828.