Historical clue formulations

• Key of Pachelbel's Canon: Abbr. — 2020-11-19
• Key of Pachelbel's Canon: Abbr. — 2018-04-18
• Baroque "key of glory": Abbr. — 2013-03-16
• Key with two sharps: Abbr. — 2011-05-24
• Key of Mahler's Symphony No. 1: Abbr. — 2009-04-17
• Key of Pachelbel's Canon: Abbr. — 2008-01-10