Historical clue formulations

• Collaborations like those on "Ella and Louis" — 2024-08-13
• Relationship strains? — 2022-09-17
• Performances by two singers ... like 21- and 49-Across and 3- and 29-Down? — 2017-06-19
• All-time best-selling Frank Sinatra album (1993) — 2016-11-02
• Airs from pairs — 2015-09-13
• Two numbers? — 2015-04-30
• 1993 triple-platinum Frank Sinatra album — 2009-02-01
• Soprano-bass combos, maybe — 2004-12-01
• 1993 Sinatra CD — 2003-01-10
• Shared airs — 1999-10-24
• Tenor-soprano combos, e.g. — 1999-02-23
• 1993 Sinatra album — 1998-03-26
• Some piano music — 1994-07-06
• 1993 Sinatra album — 1994-04-24
• Quartet after a breakup? — 1993-11-24