Waris, Abdul, and Advendi Kristiyandaru. “Penerapan Modifikasi Permainan Softball Terhadap Motivasi Belajar PJOK Siswa Kelas X SMK PGRI 13 Surabaya”. Jurnal Pendidikan Tambusai, vol. 8, no. 2, June 2024, pp. 25578-84, http://jptam.org/index.php/jptam/article/view/16130.