Sensors in Ball Argument : r/nfl
Why The NFL Puts Computer Chips In Each Football
USFL to eliminate chains, measure first downs with chip in ball and yellow line on TV, Page 2
Extra Weight Of High-Tech Chips Inserted Into USFL Footballs Reportedly Causing Problems For QBs And Kickers - BroBible
Questionable USFL First Down Sparks Debate Over Microchip Use In NFL
Break the Chain: The USFL's Virtual 1st Down Measurements Are Working
Highlight] The index card game (2017) : r/nfl
Why the NFL Still Uses Chains to Measure First Downs
American football - 3D Model 4 Sport
First-down spots limit the necessity for too many measurements – Football Zebras
The USFL Tests Football Tech. The NFL Could Adopt It. - The New York Times