Rudi Hermansyah Sitorus, Rita Kurnia and Dinda Widyastika (2025) “The effect of flash card media and problem-based learning to critical thinking skills in elementary school science lessons”, Primary: Jurnal Pendidikan Guru Sekolah Dasar, 14(5), pp. 738–747. doi:10.33578/jpfkip.v14i5.p738-747.