Susanti, N. E. (2016). PENGARUH MODEL PROBLEM BASED LEARNING TERHADAP HASIL BELAJAR GEOGERAFI SISWA SMA DI KABUPATEN MALANG. PIG (Jurnal endidikan an lmu eografi), 1(1). etrieved from http://ejournal.unikama.ac.id/index.php/JPIG/article/view/1435