NFL players union renews call for grass fields after Aaron Rodgers' injury
Dolphins players' protest during national anthem angers police
NFL Will Fine Players Who Kneel In Protest During National Anthem
Revealed: police unions spend millions to influence policy in biggest US cities, US policing
NFL Players Union Files Grievance Over League's New National Anthem Policy : NPR
NYPD suspends cops filmed assaulting protesters - ABC News
Football is here — and the NFL still doesn't know what to do about protests
Police union boycotts Browns flag ceremony after players' anthem protest, Cleveland Browns
SF Police Union Demands Apology For Colin Kaepernick's 'Ill-Advised Statements' On Police Violence - Colorlines
Benching NFL players for protesting during the anthem would be illegal - Vox