The book mentioned above may help with that, as that seems to be it's stated purpose from what I've read so far.

More will be revealed later as I get thru the book.

The Black Banjo Songsters cd from above may be something you want to check out. It has several tracks by John Snipes, and Dink Roberts who the author of the book believes is one of the oldest living(at that time,late 1970's) links to the traditional African/American banjo style.

I have a feeling the book and cd will go hand in hand as both reference each other.

BHSC