Trikalis Χ., Papanikolaou Ζ., Soulas Δ., and Gerodimos Β. “Evaluation of the Speed and Aerobic Capacity of Elite Greek Soccer Referees in A΄ and B΄ National Division”. Inquiries in Physical Education and Sport, vol. 5, no. 3, Dec. 2007, pp. 445-50, doi:10.26253/heal.uth.ojs.ispe.2007.1224.