Historical clue formulations

• Singer with the 1954 album "Frontier Ballads" — 2016-09-03
• "Turn! Turn! Turn!" songwriter — 2009-10-24
• Musician called America's Tuning Fork — 2009-10-09
• Protest music pioneer — 2008-08-29
• "Where Have All the Flowers Gone" songwriter — 1996-05-28