Saad N, Sankaran S. Development of teacher professionalism towards 21st century learning: Pembangunan profesionalisme guru ke arah pembelajaran abad ke-21. acopen [Internet]. 2020 Sep. 9 [cited 2025 Sep. 21];3:10.21070/acopen.3.2020.496. Available from: https://acopen.umsida.ac.id/index.php/acopen/article/view/496