อ้างอิง ของ กริดไอเอิร์นฟุตบอล

  1. ↑ "Gridiron football". Encyclopædia Britannica. Retrieved October 20, 2010.
  2. ↑ See, for example: Jack Brimberg and William Hurley (2006). "Strategic considerations in the coaching of North American football"[ลิงก์เสีย]. International Journal of Sport Management and Marketing. From International Journal of Sport Management and Marketing, Volume 1, Number 3, pp. 279–287.
  3. ↑ Flaherty, David H.; Manning, Frank E. (1993). The Beaver Bites Back?: American Popular Culture in Canada. McGill–Queen's Press. p. 16. ISBN 978-0-7735-1120-0.