Historical clue formulations

• Techniques — 2019-01-20
• Modi operandi — 2017-03-31
• Section of a science paper — 2015-09-24
• Techniques — 2011-03-16
• Means — 2010-06-08
• Ways — 2003-03-05
• Procedures — 1996-07-15
• Approaches — 1995-03-26