Original Source:

  http://members.aol.com/williamgunther/math.html

Text giving permission to use:

  This is just a bunch of math stuff I made for my own amusment. You can
  use these for whatever you want (profit or otherwise). If there is any
  other references or proofs you want me to try do make send me an email
  and I'll figure it out.
  ... 
  Copyright 2003-2006 William Gunther
  All Rights Reserved World Wide

Downloaded 03/01/2007