C Korngold, Farrell HM, Fozdar M: The National Football League and Chronic Traumatic Encephalopathy: Legal Implications. In: J Am Acad Psychiatry Law. 41. Jahrgang, 2013, S.430–436, PMID 24051597 (http://www.jaapl.org/search?fulltext=Korngold&submit=yes&x=0&y=0 Online Info [abgerufen am 30. Dezember 2013]).
NFL Rule Book. (PDF) Rule 12 Player Conduct. In: static.nfl.com. National Football League (NFL), S. 11 (von 73), abgerufen am 30. Dezember 2013 (englisch, Section 3 (Unsportsmanlike Conduct), Article 3 (Palpably Unfair Act)): „For a palpably unfair act: Offender may be disqualified. The Referee, after consulting his crew, enforces any such distance penalty as they consider equitable and irrespective of any other specified code penalty. The Referee may award a score.“
J Strain, Didehbani N, Cullum CM, Mansinghani S, Conover H, Kraut MA, Ghart J jr, Womack KB: Depressive symptoms and white matter dysfunction in retired NFL players with concussion history. In: Neurology. 81. Jahrgang, 2013, S.25–32, PMID 23709590.
C Korngold, Farrell HM, Fozdar M: The National Football League and Chronic Traumatic Encephalopathy: Legal Implications. In: J Am Acad Psychiatry Law. 41. Jahrgang, 2013, S.430–436, PMID 24051597 (http://www.jaapl.org/search?fulltext=Korngold&submit=yes&x=0&y=0 Online Info [abgerufen am 30. Dezember 2013]).
GW Small, Kepe V, Siddarth P, Ercoli LM, Merrill DA, Donoghue N, Bookheimer SY, Martinez J, Omalu B, Bailes J, Barrio JR: PET scanning of brain tau in retired national football league players: preliminary findings. In: Am J Geriat Psychiatry. 21. Jahrgang, 2013, S.138–144, PMID 23343487.
Danny Kelly: Alex Gibbs, the godfather of the modern zone blocking scheme. SB Nation, 25. Juli 2014, abgerufen am 30. August 2016 (englisch): „[The zone blocking scheme] origins go way back to the post-WWII era of football, if not further, and it was popularized in the NFL in Cincinnati in the late 1980s.“