Rulyansah, A.; Budiarti, R. P. N.; Rihlah, J.; Mardhotillah, R. R.; Wardhani, R. P. Application of 21st Century Learning Theory to the Improvement of Elementary School Teachers’ Pedagogical and Professional Competence: A Guide for Educators. Indones. Berdaya. 2022, 4, 61-68.