Historical clue formulations

• Physicist Fermi — 2023-12-31
• "Lucia di Lammermoor" baritone — 2018-03-22
• Physicist Fermi — 2018-01-04
• Fermi of physics — 2016-02-29
• ___ Berlinguer, longtime Italian Communist leader — 2015-03-27
• Ratso's given name — 2014-09-06
• Italian P.M. Letta — 2013-11-16
• Lucia's brother in "Lucia di Lammermoor" — 2008-09-20
• Physicist Fermi — 2008-03-02
• "Lucia di Lammermoor" baritone — 2007-06-17
• Physicist Fermi — 2006-05-10
• Baritone in Donizetti's "Lucia di Lammermoor" — 2005-08-18
• Italian dancer ___ Cecchetti — 2003-12-18
• Physicist Fermi — 2003-08-18
• Singer Caruso — 2002-02-25
• Donizetti's Lord ___ Ashton — 1999-09-04
• Physicist Fermi — 1997-09-11
• Tenor Caruso — 1997-07-07
• Physicist Fermi — 1996-05-15
• First name among tenors — 1994-09-17