Yuliyani, Rahmawati, Shinta Handayani, and Somawati Somawati. 2017. “The Role of Self Efficacy Towards Mathematical Problem Solving Ability in Terms of Positive Thinking Ability”. Unnes Journal of Mathematics Education 6 (3), 366-74. https://doi.org/10.15294/ujme.v6i3.19416.