“THE VALIDITY AND FEASIBILITY OF A HANDBOOK ON THE PROPERTIES OF LIGHT AND REFLECTIONS INTEGRATED WITH 1-SIDE HOLOGRAM LEARNING MEDIA FOR MIDDLE SCHOOL STUDENTS”. SPEKTRA: Jurnal Kajian Pendidikan Sains, vol. 11, no. 1, Apr. 2025, pp. 10-21, https://doi.org/10.32699/spektra.v11i1.8841.