Maryani, S., S. H. Respati, and O. P. Astirin. “Association Between Pregnant Woman Class and Pregnancy Complication in Tegal District, Central Java”. Journal of Maternal and Child Health, vol. 1, no. 4, Feb. 2017, pp. 214-9, http://www.thejmch.com/index.php/thejmch/article/view/31.