Kurniawati, N. 2018. PENINGKATAN DAYA RETENSI SISWA MELALUI LESSON STUDY DENGAN PBL (PROBLEM BASED LEARNING) PADA MATERI LINGKARAN. Journal of Mathematics Education and Science. 1, 1 (Apr. 2018), 35–41. DOI:https://doi.org/10.32665/james.v1iApril.15.