Muhammad Firdaus, A. Sukur, Hernawan, and R. Antoni. “The Development of Training Model of Backstroke Swimming Skills for Children Age 8-10 Years Old”. Gladi : Jurnal Ilmu Keolahragaan, Vol. 13, no. 1, Mar. 2022, pp. 1 - 14, doi:10.21009/GJIK.131.01.