Sari, D., A. Hidayati, Y. Fitria, and M. Mudjiran. “Effect of Pjbl Model and Preliminary Knowledge on Critical Thinking Skills of Grade Iv Students of Kartika Elementary School 1-11 Kota Padang”. International Journal of Educational Dynamics, Vol. 1, no. 1, Jan. 2019, pp. 205-10, doi:10.24036/ijeds.v1i1.56.