Endzone's Denver Broncos Game-Used News Archives
The Gridiron Uniform Database: 1962 Broncos Helmet Resolved (Probably)
Pro Football Journal: Denver Broncos Helmet Oddity in 1976 and 1977—Two Shades of Blue
Seattle Seahawks Spirit of 1976 Page
Pro Football Journal: Another Uniform Oddity. The 1977 Pro Bowl
Lot Detail - 1970s-80s Craig Morton Denver Broncos Game-Used Helmet
Pro Football Journal: Denver Broncos Helmet Oddity in 1976 and 1977—Two Shades of Blue
NFL History: 100 objects that tell the story of football - Sports Illustrated
Endzone's Denver Broncos Game-Used News Archives
Pro Football Journal: Denver Broncos Helmet Oddity in 1976 and 1977—Two Shades of Blue