Sari, S., T. Pandiangan, J. Harahap, and Y. Yanti. “COMBINATION OF BABY EXERCISE AND CLASSICAL MUSIC TOWARDS SLEEP DURATION OF 3 MONTHS BABIES”. JURNAL IBU DAN ANAK, Vol. 9, no. 2, Jan. 2022, pp. 70-74, https://jurnal.pkr.ac.id/index.php/JIA/article/view/395.