EXPLAINER: NFL using helmet caps for player safety, research
NFL exec suggests Guardian Caps worn to protect players during practices could one day debut in games
Guardian Cap Use a Concern for Watt, Saleh Early in Training Camp - Sports Illustrated
Complaints begin regarding Guardian Caps, despite one important hidden benefit - NBC Sports
Cowboys seen wearing protective, NFL mandated Guardian Caps at OTAs
Guardian cap' to prevent head injuries mandated for practices, CFL says
EXPLAINER: NFL using helmet caps for player safety, research - The San Diego Union-Tribune
Notebook Jets HC Robert Saleh Assesses the Guardian Helmet
Guardian Caps debut at NFL training camps around the league
NFL: Concussions dropped by more than 50% among players who wore Guardian Caps during summer