Namgyal, T., & Kongmanus, K. (2018). 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(4.38), 965-969. https://doi.org/10.14419/ijet.v7i4.38.27618