Akma, T. and man, S. 2018. The Design of Student Worksheet Problem based Learning to Improve Problem Solving Ability of the Eighth-Grade Students Junior High School in Indonesia. International Journal of Engineering & Technology. 7, 4.30 (Nov. 2018), 11–15. DOI:https://doi.org/10.14419/ijet.v7i4.30.21993.