Historical clue formulations

• Networks: Abbr. — 2016-04-21
• Operating procedures: Abbr. — 2014-04-27
• Ways of operating: Abbr. — 2012-07-25
• Methods: Abbr. — 2009-06-25
• Ways: Abbr. — 2006-01-06
• M.O.'s — 2004-12-09
• Methods: Abbr. — 2004-09-29
• Methods: Abbr. — 2003-09-23
• Procedures: Abbr. — 2003-01-17
• Methods: Abbr. — 2001-01-04