Safety measures: NFL hopes to reduce head injuries with helmet experiment at camps, Sports
NFL: Guardian Cap debuts during minicamps in effort to reduce avoidable head contact
NFL Mandated Guardian Caps: Controversial Change - Sports Illustrated Seattle Seahawks News, Analysis and More
Guardian Caps Exceed NFL's Expectations - Guardian Sports
Coverage of the NFL in Guardian Caps
EXPLAINER: NFL using helmet caps for player safety, research
If a player wanted to wear a Guardian Cap during a game, the league would prohibit it - NBC Sports
Shell game: Player safety looming concern as new season approaches, Local Sports
[Smith] NFL says positions wearing Guardian Caps saw 52% decrease in concussions : r/nfl
NFL CMO Dr. Sills on Guardian Caps Mandate >> Guardian Sports
Guardian Cap Use a Concern for Watt, Saleh Early in Training Camp - Sports Illustrated
Guardian Caps - Are the soft-shelled football helmet covers effective at limiting head injuries? - ESPN
NFL's use of Guardian padded helmet caps in camp draws support and skepticism - The Athletic
Funky-Looking Guardian Caps Rejected by NFL for Regulation Play, OK'd for Practice - Core77