Pete Seeger through the years

FILE: Sept. 21, 2013: Pete Seeger performs on stage during the Farm Aid 2013 concert at Saratoga Performing Arts Center in Saratoga Springs, N.Y. The American troubadour, folk singer and activist Seeger died Monday Jan. 27, 2014, at age 94. (AP)

FILE: Sept. 21, 2013: John Mellencamp, left, and Pete Seeger on stage during the Farm Aid 2013 concert at Saratoga Performing Arts Center in Saratoga Springs, N.Y. (AP)

This 1967 file photo shows Pete Seeger. The American troubadour, folk singer and activist Seeger died Monday Jan. 27, 2014, at age 94 (AP)

This May 1993 file photo shows Pete Seeger, left, age 74, who hadn't sung with Burl Ives, right, age 84, for at least 40 years, singing together in rehearsal at New York's 92nd St., Y. (AP)

This April 4, 1961, file photo shows American folk singer Pete Seeger, a banjo slung over his shoulder, being accompanied by his wife Toshi, on his arrival at the Federal Court, in New York. (AP)

This Oct. 14, 1994, file photo shows President Clinton presenting folk musician Pete Seeger with a 1994 National Medal of Arts, in Washington at the White House. (AP)