I've got a very early work by Antony Scaduto, which I remember as being very good. I got it the year it was published (1972) but I can't remember if that's where I came across the Van Ronk stuff. I'll have a look. Incidentally, did you see the Oscar Isaac(s?) film called something like Searching For Lewin Davies? That's supposed to be about a character who may or may not be Van Ronk. whatever, it's a good fillum.
It's all a bit academic - Bob has stolen so much stuff over the years he ought to get the Nobel Prize For Sampling. He was years ahead in that field, as he has been in most!
PS all written without leaving the sofa - or couch, as we have it up here.