Historical clue formulations

• Original and influential — 2025-04-17
• Formative — 2023-02-02
• Formative — 2019-06-09
• Original — 2012-01-08
• Formative — 2010-09-03
• Original — 2010-02-22
• Primary — 2006-01-27
• Formative — 2003-10-25
• Formative — 2001-02-11
• Highly influential — 1999-06-23