Simanjuntak, Jetri Jogi, et al. “The Effect of Wrist Flexibility Exercise Using a Bottle on the Ability of Smash Badminton at the Extracurricular of SMK Negeri 2 Palembang”. Journal of Social Work and Science Education, vol. 4, no. 3, June 2023, pp. 584-90, doi:10.52690/jswse.v4i3.594.