Welan, Clive Johday. 2023. “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]”. Kumpulan Artikel Ilmiah Rumpun Ekonomi Dan Ilmu Sosial 3 (1):88-107. https://doi.org/10.19166/kairos.v3i1.6145.