Ranking all 32 NFL helmets from worst to first
Helmet Laboratory Testing Performance Results
NFL teams are using a new, safer helmet — the Vicis Zero1
Ranking college football's 10 best helmets - Page 11
Top 10 NFL Helmets of All-Time
My Top 10 best NFL helmets of all time
VICIS has top 3 helmets in survey including lineman model
Ranking all 32 NFL helmets from worst to first
Sources -- AB says no football without old helmet - ESPN
What Pros Wear: Top 5 Helmets Rated by the NFL & NFLPA - What Pros