Jaenudin, Irfan, et al. “Content Analysis of the Nature of Science on Elementary Thematic Textbooks 2013 Curriculum”. Premiere Educandum : Jurnal Pendidikan Dasar Dan Pembelajaran, vol. 11, no. 2, Sept. 2021, pp. 227 – 242, doi:10.25273/pe.v11i2.9187.