Lyons, B. D.; Hoffman, B. J.; Michel, J. W.; Williams, K. J. (2011). "On the Predictive Efficiency of Past Performance and Physical Ability: The Case of the National Football League". Human Performance. 24 (2): 158. doi:10.1080/08959285.2011.555218. S2CID143657167.
Lyons, B. D.; Hoffman, B. J.; Michel, J. W.; Williams, K. J. (2011). "On the Predictive Efficiency of Past Performance and Physical Ability: The Case of the National Football League". Human Performance. 24 (2): 158. doi:10.1080/08959285.2011.555218. S2CID143657167.