Karyadi, P.A. et al. 2020. ANALYSIS THE 21ST CENTURY SKILLS OF STUDENTS IN CHEMICAL EQUILIBRIUM LEARNING WITH FLIPPED CLASSROOM-COLLABORATIVE PROBLEM SOLVING MODEL. JTK (Jurnal Tadris Kimiya). 5, 1 (Jun. 2020), 48–60. DOI:https://doi.org/10.15575/jtk.v5i1.7971.