Ummah, S. M.; Astutik, A. P. Implementation of Problem Based Learning to Improve The Quality of PAI Learning During The Covid-19 Pandemic at School: Implementasi Problem Based Learning Untuk Meningkatkan Kualitas Pembelajaran PAI Selama Pandemi Covid-19 Di Sekolah. acopen 2022, 6, 10.21070/acopen.6.2022.2145.