Historical clue formulations

• Choices on a standard Scantron test — 2018-01-12
• Start of a children's rhyme — 2004-04-22
• Kindergarten song starter — 2002-11-16
• Start of kindergarten learning — 2001-01-22
• Start of a series — 1999-07-14
• Start of a well-known series — 1998-08-12