Historical clue formulations

• Joe known as "The Comeback Kid" — 2018-03-09
• Where the Missouri River begins — 2017-10-15
• Cattle drive destination in "Lonesome Dove" — 2015-10-02
• State with the motto "Oro y plata" — 2014-07-20
• State with a bison skull on its quarter — 2012-10-11
• See 26-/28-Down — 2011-06-02
• Its flag depicts a plow, shovel and pick — 2007-07-07
• Flathead Indians' home — 2001-07-12
• Fort Peck site — 1996-04-26
• Where the Tongue River flows — 1996-03-09
• Four-time Super Bowl QB — 1994-06-30
• Four-time Super Bowl QB — 1994-03-11