DEVELOPMENT OF POP-UP BOOK MEDIA FOR SPATIAL CONSTRUCTION MATERIALS FOR FOURTH GRADE STUDENTS AT STATE ELEMENTARY SCHOOL 121309 GURILLA PEMATANGSIANTAR. Jurnal Merah Putih Sekolah Dasar, The Indonesian Journal of Primary School Education [Internet]. 2024 Jan. 15 [cited 2026 Apr. 7];1(1):18-26. Available from: https://jurnal.unimed.ac.id/2012/index.php/jmpsd/article/view/56072