Blatsis, Petros, Ploutarhos Saraslanidis, Vassileios Barkoukis, Vassiliki Manou, Kostas Tzavidas, Hristos Hatzivasiliou, and Stamatia Palla. 2016. “Does the Background of a Long Term Involvement in Extra Curricular Sports Affect the Physical Fitness Differences Between Preadolescent Boys and Girls?”. Inquiries in Physical Education and Sport 14 (3):49-61. https://doi.org/10.26253/heal.uth.ojs.ispe.2016.1482.