Historical clue formulations

• Vouch for — 2021-07-29
• Swear is true — 2020-02-26
• Vouch for — 2019-12-01
• Confirm — 2014-06-07
• Certify — 2011-07-07
• Certify — 2001-05-06
• Certify — 2000-11-26