Sukmasari, D., and I. Murniawaty. “Peningkatan Kemampuan Berpikir Kritis Siswa Melalui Model Pembelajaran Group Investigation Berbasis Lesson Study”. Economic Education Analysis Journal, Vol. 8, no. 3, Nov. 2019, pp. 1097-14, doi:10.15294/eeaj.v8i3.35713.