Igoe, Brett Allan, and Declan Browne. “Maximum Ball in Play Demands for Sub-Elite Rugby Union Referees in Domestic Club Rugby”. Journal of Human Sport and Exercise 15, no. 3 (September 1, 2020): 478–488. Accessed June 21, 2024. https://www.jhse.ua.es/article/view/2020-v15-n3-maximum-ball-play-demands-sub-elite-rugby-union-refe.