Guardian Caps: The new helmets worn by several NFL teams
Riddell NFL Crucial Catch Mini Helmet
Vicis expands funding round with help from NFL quarterbacks Alex Smith and Aaron Rodgers - Puget Sound Business Journal
The NFL calls Vicis Zero1 helmets the safest yet
Photos: Bold helmet designs for NFL teams
Seattle company designs safest football helmet in the country
John Gordon, artist who helped design Packers' distinctive 'G' team logo, dies at age 83, National
Sports equipment maker Defend Your Head files for bankruptcy - Philadelphia Business Journal
EXPLAINER: NFL using helmet caps for player safety, research
Guardian Caps - Are the soft-shelled football helmet covers effective at limiting head injuries? - ESPN