Historical clue formulations

• Whit — 2016-02-18
• Taxonomy suffix — 2012-05-05
• Do, re or mi, in Italy — 2006-04-01
• Hiroshima's river — 2005-06-11
• Taxonomic suffix — 2002-06-22
• Suffix in taxonomy — 1996-05-16
• Hiroshima's river — 1996-03-08