G. Tampubolon, H. Sianturi, J. Sitotus, Y. Simbolon, R. Siregar, and L. Tansliova, “Using Problem Based Learning (PBL) to Improve Critical Thinking Skills and Indonesian Language Skills”, Jurnal Multidisiplin Indonesia, vol. 3, no. 1, pp. 843–847, Jun. 2024.