Siregar, Tanti Jumaisyaroh. 2018. “THE INFLUENCE OF PROBLEM-BASED LEARNING ON IMPROVING STUDENTS’ SELF-EFFICACY ATTITUDES”. REKOGNISI : Jurnal Pendidikan Dan Kependidikan (E-ISSN 2599-2260) 3 (1):117-29. https://jurnal.unusu.ac.id/index.php/rekognisi/article/view/83.