No order that I know of....

Bob Gibson
Bob Camp
Dave Van Ronk
Doc Watson
Schooner Fare
PP&M
Huddie Ledbetter
Odetta
Joan Baez
Tom Paxton
Stan Rogers (and don't give me any crap!)
Tommy Makem (and his sons)
Arlo and Woody Guthrie
Kendall Morse
Art Thieme
Phil Ochs
SOME of Bob Dylan
Judy Collins
Chad Mitchell Trio
John Denver
Pete Seeger
Buffy Ste. Marie
Big Mama Thornton
Billy Holliday
Patsy Cline
and a whole lot of other people.