Another one is Sikorsky Helicopter Flight Theory for Pilots and Mechanics, you used to get them from Sikorsky when you did a course there, I don't think they still do them, there is a learning programme that goes with it as well, please bear in mind that the terminology will be different, the chapter on autorotation is the best I have read. There is also a huge amount of information available on-line that you can find with a diligent search