J. M. Gamonales, M. Ángel Salgado-Santos, and S. J. Ibáñez, “Influence of Means of Initiation to Training in The Design of Tasks in Soccer in The School Age (U12)”, MHSalud, vol. 18, no. 2, pp. 1–15, Jul. 2021, doi: 10.15359/mhs.18-2.10.