I am a fan- I competed against some of his boys - way back when
and at the time - they set the standard of training.
he is kind of a mean old bastard to say the least
there are a couple of books about him
amazon can help you there
a book about him
A Season on the Mat: Dan Gable and the Pursuit of Perfection
there are a few more about him- mostly about his olympic run
coaching mental toughness on the mat
coaching wrestling sucessfully
he wrote both of these- Im sure with help and they are excellent.
there are some good interviews out there- flow wrestling has many