Wandini, Rora, 		Damanik, Emeliya Sukma, AND 		Iskandar, Wahyu.
" Analysis of Problem Solving Ability Students Mathematis PGMI UINSU Based Zone of Proximal Development Of Students Primary School" <em>Proceeding of International Conference on Islamic Education (ICIED)</em> [Online], Volume 4 Number 1 (24 December 2019)