Setiawan, Adi, Sariyatun Sariyatun, and Deny Tri Ardianto. “The Innovation of Democratic Education: The Development of Learning Approach Based on the Sutan Syahrir’ Thought to Strengthen Students’ Democratic Attitude”. Yupa: Historical Studies Journal 2, no. 2 (December 31, 2018): 105-114. Accessed September 24, 2020. http://jurnal.fkip.unmul.ac.id/index.php/yupa/article/view/121.