NFL hopes to reduce head injuries with helmet experiment, Sports
NFL CMO Dr. Allen Sills explains importance of mandated guardian caps during training camp
Complaints begin regarding Guardian Caps, despite one important hidden benefit - NBC Sports
Guardian cap' to prevent head injuries mandated for practices, CFL says
Why are NFL players wearing padding on helmets at training camp?
NFL Mandates Guardian Caps >> Guardian Sports
Guardian Caps Guardian Sports
NFL training camps: Guardian Cap players are wearing over helmets, why
Guardian Cap: What are and why the NFL asks this safety measure in helmets
NFL hopes to reduce head injuries with helmet experiment
Could Guardian Caps be used in games? - NBC Sports
Puffy, spongy Guardian Caps could help curb NFL head injuries - The Washington Post
NFL to expand use of Guardian Caps in preseason, regular season practices - NBC Sports