Handbook for tosion spring calculation 1

[alone_dancer]

Hi All,
I'm designing a torsion spring. I got an excel calculation tool from the internet.
Does anyone know which book the following pictures are from? I want to get more information about it.

Thanks

 

[3DDave]

It looks to be from this:

http://www.faculty.fairfield.edu/wdornfeld/ME311/AssocSpringBarnes-SpringDesignHandbook.pdf

 

[alone_dancer]

Thanks for your sharing, 3DDave! Really appreciate!