Haswadi, M., .-. Syarifudin, and .-. Rusdiawan. “Children Phonological Acquisition for 3 to 5-Year-Olds”. International Journal of Linguistics, Literature and Culture, vol. 4, no. 1, Jan. 2018, pp. 16-21, https://sloap.org/journals/index.php/ijllc/article/view/68.