The article describes how Hellman took up banjo:
It was also around that time that Hellman discovered the banjo. He bought an instruction book, “How to Play the 5-String Banjo,” by folk legend Pete Seeger. Frustrated at how slowly he was learning, Hellman decided he wanted to take lessons from Seeger himself and called up the singer’s manager. Hellman took it in stride when he was rejected.We offer no promises that it will turn you into a billionaire, but the library does have Pete Seeger's book, MT562.S44 H6.
The Billionaire Who Loved Bluegrass