Thanks to Michael Gray:
“Re your posting re rare early Dylan books: there is a fair amount of detail on both the Ribakoves’ book and the Dave Engel book in The Bob Dylan Encyclopedia.
“Since the entries are people-based, as you know, you’ll find the info on these books under the authors’ names.
“I describe Engel’s Just Like Bob Zimmerman’s Blues: Dylan in Minnesota as “one of the four or five most valuable books on Bob Dylan”: a view I stand by.”
www.bobdylanencyclopedia.blogspot.com