Pro Football Journal: The 1969 Vikings and Their Three Purple Jerseys
Heritage Uniforms and Jerseys and Stadiums - NFL, MLB, NHL, NBA, NCAA, US Colleges: Minnesota Vikings Uniform and Team History
Digit Dominance: Ranking the best QBs by jersey numbers - ESPN
Who is your favorite obscure/forgotten NFL quarterback? - Quora
Every Fran Tarkenton Touchdown (Playoffs)
69 Joe Kapp Vikings Stock Photos, High-Res Pictures, and Images - Getty Images
JOE KAPP Minnesota Vikings 1969 Wilson Throwback Away NFL
Minnesota Vikings Qb Joe Kapp Sports Illustrated Cover by Sports Illustrated
Minnesota Vikings – Page 3 – Fan HQ
Jim Zorn QB Classic (c.1979) Seattle Seahawks Football Premium Poster Print - Photofile Inc. – Sports Poster Warehouse