Explaining Antonio Brown's helmet issue: What are the NFL's rules, Raiders' options, AB's contract?
An Idiot's Guide to the Antonio Brown Helmet Grievance - The Ringer
Sources -- AB says no football without old helmet - ESPN
Report: Antonio Brown threatens retirement over new NFL helmet restrictions
Report: Antonio Brown Threatens to Quit Football over Helmet Grievance, News, Scores, Highlights, Stats, and Rumors
Antonio Brown - Wikipedia
Antonio Brown gets endorsement deal after 'helmet-gate', Raiders News
Raiders' Antonio Brown Loses Helmet Grievance - The New York Times
NFL: Antonio Brown could be in 'breach of contract' if he won't play in new helmet
Antonio Brown and Tom Brady aren't happy about helmet switch - Los Angeles Times
Antonio Brown's Helmet Standoff Nears a Conclusion - The New York Times
Explaining Antonio Brown's helmet issue: What are the NFL's rules, Raiders' options, AB's contract?
Antonio Brown threatens to quit Raiders over helmet rule: report