Devi, S., and muhamad rifki. “PENGARUH METODE DRILLS UNDER SIMPLIFIED CONDITIONS TERHADAP KEMAMPUAN SERVIS ATAS BOLAVOLI KLUB GESIMPO PASAMAN BARAT”. JURNAL STAMINA, Vol. 2, no. 9, Sept. 2019, pp. 87-92, http://stamina.ppj.unp.ac.id/index.php/JST/article/view/355.