Sanigraha, B. and Setiawan, I. (2019) “The Improvement of Students’ Understanding in Spring Energy Concept through Constructivisme Model of Learning”, Wahana Journal of Action Research, 1(1), pp. 1-9. Available at: http://jurnal.sman1parung.sch.id/index.php/jar/article/view/2 (Accessed: 19September2019).