Rules for the national anthem differ across sports leagues - ESPN
How Fans Are Reacting to the NFL Anthem Protests - Sports Illustrated
NFL players kneeling during national anthem: How Colin Kaepernick started a movement and why – The Daily Egyptian
What Cowboys past and present think of national anthem protests — and how Jerry Jones' team handled them
Taking the knee: These are the NFL players protesting today
Taking the knee: These are the NFL players protesting today
Steelers choose to remain in locker room during national anthem, team president Art Rooney backs players – New York Daily News
Here's how NFL players protested during national anthems on Sunday, Monday of Week 1
NFL national anthem protest: List of players who have kneeled - Sports Illustrated