NFL: Empty NFL stadiums leave NFL 'eerie' feeling for players, coaches
Study: With masking and distancing in place, NFL stadium openings in 2020 had no impact on local Covid-19 infections, MIT News
How the NFL navigated COVID-19 this season - 959,860 tests, $100 million and zero cancellations - ESPN
NFL Health and Safety Fact Sheet
Public health implications of opening National Football League stadiums during the COVID-19 pandemic
Packers put 'indefinite hold' on fans being in Lambeau this season
Even In A Pandemic, The NFL Is Ready To Dominate The Sports Landscape : NPR
What we can learn about economics from professional sport during Covid-19
COVID is threatening NFL's bottom line of $16 billion
New Study Finds Covid Spikes After N.F.L. Games With Fans - The New York Times
N.F.L. Team Thrown by False Positive Covid-19 Tests - The New York Times