Arya, Anand Kumar, and Narendra Pal. “Periodic Table As a Constructivist Model of Teaching-Learning at the Secondary Level”. SCHOOL SCIENCE 55, no. 2-3 (September 30, 2017): p.88–92. Accessed April 28, 2025. http://14.139.250.109:8090/index.php/SS/article/view/2527.