Michael Poliakoff: [<http://search.eb.com/eb/article-29781 boxing] (Early years) Encyclopædia Britannica Online. 2009. Encyclopædia Britannica. Viitattu 26.11.2009. (englanniksi)
Encyclopædia Britannica: [<http://search.eb.com/eb/article-29782 boxing] (The bare-knuckle era) Encyclopædia Britannica Online. 2009. Encyclopædia Britannica. Viitattu 26.11.2009. (englanniksi)
Thomas Hauser,Jeffrey Thomas Sammons, Ed.: boxing (The Queensberry rules) Encyclopædia Britannica Online. 2009. Encyclopædia Britannica. Viitattu 26.11.2009. (englanniksi)