Sumarni, Sri, et al. “Project Based Learning (PBL) Based Lesson Study for Learning Community (LSLC) in Kindergarten”. Jurnal Obsesi : Jurnal Pendidikan Anak Usia Dini, vol. 6, no. 2, July 2021, pp. 989-96, doi:10.31004/obsesi.v6i2.1637.