Widyawati, W., E. P. Pamungkasari, and B. Murti. “Contextual Effect of the Community Health Center on the Use of Antenatal Care: A Multilevel Analysis Evidence from Semarang, Central Java”. Journal of Maternal and Child Health, vol. 5, no. 6, Nov. 2020, pp. 663-72, http://thejmch.com/index.php/thejmch/article/view/507.