Namgyal, Tenzin, and Kobsook Kongmanus. “Effectiveness of a Mathematics Instructional Package on Pólya’s Steps Including Video Clips to Enhance Problem Solving Abilities of 6th Grade Students in Bhutan”. International Journal of Engineering & Technology 7, no. 4.38 (December 3, 2018): 965–969. Accessed May 3, 2024. https://sciencepubco.com/index.php/ijet/article/view/27618.