Y. T. Agustin, Y. E. Gunanto, en T. Listiani, ‘Hubungan Motivasi Belajar dan Disiplin Belajar Siswa Kelas IX Pada Pembelajaran Matematika di Suatu Sekolah Kristen [The Relationship between Learning Motivation and Learning Discipline of Grade 9 Mathematics Students at a Christian School]’, JOHME, vol. 1, nr. 1, pp. 32–40, dec. 2017.