Maria และ Josefina Umali Sta. (1998) Age at first marriage in the Philippines : evidence from the 1993 National Demographic Survey. Mahidol University,:ม.ป.ท.Maria และ Josefina Umali Sta. 1998. Age at first marriage in the Philippines : evidence from the 1993 National Demographic Survey. ม.ป.ท.:Mahidol University,;Maria และ Josefina Umali Sta. Age at first marriage in the Philippines : evidence from the 1993 National Demographic Survey. ม.ป.ท.:Mahidol University, 1998. Print.