Ajman, Hrvoje, and Zvonimir Tomac. 2019. “Differences in Biological Age of the Best U11 and U13 Teams in Croatia”. Journal of Human Sport and Exercise 14 (5proc):S2375-S2379. https://www.jhse.ua.es/article/view/2019-v14-n5-proc-biological-age-best-u11-u13-teams-croatia.