Rahadianto, Irfan Dwi, et al. “Analysis of Merrill’s First Principles of Instruction in the Educational VR Game ’Titans of Space’ With a Formal Element Approach”. Jurnal Penelitian Pendidikan, vol. 23, no. 3, Dec. 2023, pp. 251-77, https://doi.org/10.17509/jpp.v23i3.62676.