Supriyantoro, Dwi, Meini Sondang Sumbawati, and Nurmida Catherine Sitompul. “Pengembangan Perangkat Pembelajaran IPA Dengan Model Problem Based Learning Berbasis Outdoor Learning”. Jurnal Pijar Mipa 14, no. 2 (July 23, 2019): 42–48. Accessed January 30, 2023. https://jurnalfkip.unram.ac.id/index.php/JPM/article/view/1136.