Since hearing of Bert's death, I've been playing his first album, and it occured to be that his playing on that album is particularly American influenced on a number of tracks.
On "Needle of Death" and "Running from Home", foe example, is uses - what we called back then - "clawhammer style"; today, it seems to be called "pattern playing".
Now, Dylan, Phil Ochs, Joan Baez etc used this style but Bert elevates the style on to a much higher level.
The lovely touches that he adds to the guitar part of "Running from Home" are just marvelous.
He certainly was very special.