M. Hafiz, A. Asmar, and Y. Yerizon, “The Effect of Problem Centered Learning (PCL) Approach to Critical Thinking Skills of Class XI MAS Tanah Datar District”, J. Pend. Mat. Rafa, vol. 6, no. 1, pp. 1–14, Jun. 2020, doi: 10.19109/jpmrafa.v6i1.4579.