FILE - Folk trio Peter, Paul and Mary, from left, Mary Travers, Paul Stookey and Peter Yarrow, perform at a Los Angeles benefit to aid to Cambodian refugees on Jan. 30, 1980. (AP Photo/George Brich, File)

FILE - Folk trio Peter, Paul and Mary, from left, Paul Stookey, Mary Travers and Peter Yarrow, appear at the American Music Awards in Los Angeles, Jan. 26, 1987. (AP Photo/Lennox McLendon, File)

FILE - Singer-songwriter Peter Yarrow, of the 1960's era musical trio "Peter Paul and Mary," performs during a memorial tribute concert for folk icon and civil rights activist Pete Seeger in New York on July 20, 2014. (AP Photo/Kathy Willens, File)

FILE - Peter Yarrow attends the premiere of "While We're Young" at the Paris Theatre on March 23, 2015, in New York. (Photo by Charles Sykes/Invision/AP, File)