Welan CJ. PENERAPAN MODEL PROBLEM SOLVING LEARNING UNTUK MENINGKATKAN HASIL BELAJAR KOGNITIF SISWA KELAS XI PADA MATERI KONFLIK SOSIAL DI SALAH SATU SMA DI SURABAYA [THE IMPLEMENTATION OF PROBLEM-SOLVING LEARNING MODELS TO IMPROVE STUDENTS COGNITIVE ACHIEVEMENT ON CONFLICT OF GRADE XI SENIOR HIGH SCHOOL IN ONE OF THE HIGH SCHOOL IN SURABAYA]. KAIROS [Internet]. 2023 Feb. 16 [cited 2025 Jan. 31];3(1):88-107. Available from: https://ojs.uph.edu/index.php/KAIROS/article/view/6145