Protective equipment in gridiron football - Wikipedia
For Various Reasons, N.F.L. Players Do Not Wear Cups - The New York Times
These Carbon Fiber Shoulder Pads Absorb Even NFL-Sized Hits
What's the deal with Georgia players no longer wearing knee pads?
Ask Sam Farmer: How much does an NFL uniform weigh? - Los Angeles Times
NFL, players adjusting to mandatory knee, thigh pad rule change
NFL makes knee and thigh pads mandatory for 2013-14 season
The history of football uniforms - NPP
NFL At 100: From head to toe, players equipment has evolved
7 Pieces of Protective American Football Gear From Nike to Buy Now. Nike CA
The N.F.L.'s Incredible Shrinking Pads - The New York Times
NFL will remove players from games for not wearing knee or thigh pads