Best Football Cards of the 80s
The Hardest John Elway Football Cards to Collect: 1984–1996 - HobbyLark
John Offerdahl Trading Cards: Values, Tracking & Hot Deals
John Offerdahl Trading Cards: Values, Tracking & Hot Deals
1989 Topps Football #295 John Offerdahl B2
The Mystery and Rarity of the 1960 7-Eleven Dallas Texans Football Card Set – Post War Cards
Prices Realized — Auction Time Bid Board
Mystery card packs, Notre Dame football legends highlight Chicago Card Show - Sports Collectors Digest