Add: Hills, etc., "Never Grow Up"
    Post, Jim - Friends
    Best of Friends - their one and only cd, sadly
    Nitties, all the Circles
    Gillette, Steve - most all
    Kweskin, Jim - most all
and Jim Rooney's book on the early days in Boston.
This omits the trove of great Chicago folk music (e.g. Art Thieme, Tom Dundee, John Prine, Steve Goodman, Michael Smith, Bonnie Koloc, Kendall Kardt, Redhead), but that would require an even longer list.
I think these have withstood the test of time.

Chris