Historical clue formulations

• "Please demonstrate" — 2022-11-15
• "Prove it!" — 2015-11-15
• "Prove it!" — 2015-04-26
• "Prove it!" — 2010-07-11
• "You'll have to demonstrate" — 2009-09-22
• "Prove it!" — 2008-04-15
• "Prove it!" — 2002-12-11
• Missourian's demand — 2002-07-22