Athiyyah , Royhanun, Taufiq Al Farizi, and Dwi Nanto. “Improvement of Science Process Skills Through Sound Variable Intensity Level Tool Kit”. Jurnal Penelitian & Pengembangan Pendidikan Fisika 6, no. 1 (June 30, 2020): 89 - 96. Accessed November 20, 2025. http://103.8.12.212:33180/unj/index.php/jpppf/article/view/12829.