A closer look at the rule changes the NFL is debating - The Washington Post
The story behind those soft-shell puffy Guardian Caps players have been wearing
Coverage of the NFL in Guardian Caps
Puffy Guardian Caps Could Reduce NFL Player Concussions
Guardian Cap debuts during minicamps in effort to reduce avoidable head contact
Arizona Wildcats football training camp report: Day 3 - Arizona Desert Swarm
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
Guardian Caps: NFL's hotly debated new safety measure here to stay?
NFL says Guardian Caps reduced concussions by over 50%
What are Guardian Caps? Shadow Hills football using new device to reduce head injuries
Why Utah players wore Guardian Caps during camp - Deseret News
NFL executive hints that Guardian Caps could eventually be worn in games, along with position-specific helmets
Why Alabama football players are wearing padded helmets in practice
Guardian Caps - Are the soft-shelled football helmet covers effective at limiting head injuries? - ESPN