“The Contribution of Concentration and Confidence to Penalty Kick Success in U-13 Football Players of SSB Balasuga Semarang”, Compet. J. Pendidik. Kepelatihan Olahraga, vol. 18, no. 2, pp. 2481–2493, May 2026, doi: 10.26858/cpjok.v18i2.740.