Canapini, L., C. H. Varde’i, A. Cejudo-Palomo, and R. Izzo. “Analysis of the Physical Efficiency Index in Football Teams and Correlation With Goal Events: A Survey of the Italian Serie A Championship”. Journal of Human Sport and Exercise, vol. 14, no. 5proc, Dec. 2019, pp. S2390-S2399, https://www.jhse.ua.es/article/view/2019-v14-n5-proc-physical-efficiency-index-football-teams-goal-e.