1. Pole Vault Olympic Records (Men's);
http://www.olympic.org
(2012).
2. International Association of Athletics Federation (IAAF) Pole Vault Competition Rules;
http://www.iaaf.org
(2012).
3. Fédération Internationale de Football (FIFA) Football's Equipment Evolution;
http://go.nature.com/xdZTaf
(2012).
4. Froes, F. H. JOM 49, 15–19 (1997).
5. Fédération Internationale de Natation (FINA) Swimming Rules and Regulations;
http://www.fina.org
(2012).