Interesting. The public domain material was never credited to the public domain. The Trio would make some changes and claim the writing credits themselves. The Weavers did the same thing. Paul Campbell was the Weavers' group pseudonym. For a while, the Trio used Jack Splittard as a group pseudonym. Many of the folk groups did quite nicely rewriting and rearranging material from the John and Alan Lomax collections.

Josh is correct. None of the singer-songwriters of the '60s was established when Dave left. The Trio did record material by Dylan, Tom Paxton and Gordon Lightfoot but by that time (1963 and after), the Trio's album sales were declining. One singer-songwriter the Trio latched onto was Mason Williams. They recorded a lot of his stuff, but except for Classical Gas, Williams never really established himself as a big-time songwriter.

Nick used to tell the story that when Dylan was still an unknown, Albert Grossman, Dylan's manager, sent the Trio a demo tape of Dylan's great early songs, apparently to give the Trio the first shot at recording them. But, according to Nick, no one bothered to listen to the tape that Grossman sent them. Think about that missed opportunity for a minute!