Nasbey, H., G. Raharjo, and R. Razali. “PENGEMBANGAN ALAT PERAGA GERAK PARABOLA MENGGUNAKAN PELONTAR PROYEKTIL OTOMATIS”. PROSIDING SEMINAR NASIONAL FISIKA (E-JOURNAL), Vol. 1, no. 1, Oct. 2012, pp. 137 -39, https://journal.unj.ac.id/unj/index.php/prosidingsnf/article/view/6171.