Retnowati, Fitri, Nur Karomah Dwidayati, and Nuriana Rachmani Dewi. 2019. “The Implementation of CPS Learning Assisted With Problem Cards on The Ability to Solve Story Problems”. Journal of Primary Education 8 (6), 351-57. https://journal.unnes.ac.id/sju/jpe/article/view/33685.