Recommendations of the Polish Society of Sports Medicine on age criteria while qualifying children and youth for participation in various sports
Tomasz Kostka, Witold Furgal, Wojciech Gawroński, Andrzej Bugajski, Andrzej Czamara, Krzysztof Klukowski, Hubert Krysztofiak, Romuald Lewicki, Zbigniew Szyguła, Wiesław Tomaszewski, Tadeusz Trzaska, Jerzy Widuchowski, Andrzej Ziemba, Anna Jegier
British Journal of Sports Medicine Mar 2012, 46 (3) 159-162; DOI: 10.1136/bjsports-2011-090043