Sulasiwi, Intan Febry, Supriyono Koes Handayanto, and Wartono Wartono. “Development of Self-Rating Scale Instrument of Self-Directed Learning Skills for High School Students”. Jurnal Penelitian dan Evaluasi Pendidikan 23, no. 1 (June 29, 2019): 1–11. Accessed June 6, 2025. https://jurnal.uny.ac.id/index.php/jpep/article/view/18130.