Suprapto, E., Setyansah, R. K., & Devina, D. (2021). GeoGebra Application Based Tutorial Materials to Improve Spatial Mathematics Abilities in Vocational High Schools. Jurnal Pendidikan Teknologi Dan Kejuruan, 27(2), 175–181. https://doi.org/10.21831/jptk.v27i2.39099