Suryaningsih, Endang Koni, and Meei Ling Gau. “Factor Influence Pre-Marital Pregnancy in Yogyakarta, Indonesia: A Qualitative Study”. Journal of Health Technology Assessment in Midwifery, vol. 4, no. 1, Mar. 2021, pp. 1-7, doi:10.31101/jhtam.1371.