M. Irfan, A. S. Harahap, Khairul Usman, Hariadi, and M. N. Hasibuan. “PROTOTIPE INDUSTRI OLAHRAGA EDU ORTRAD UNIMED”. Bina Guna Press, Sept. 2023, pp. 1-64, https://jurnal.stokbinaguna.ac.id/index.php/BGP/article/view/1387.