Here's another one for you.
http://thyroid.about.com/cs/testsforthyroid/a/freet3.htm
This is link to an article I use a lot as a reference.
http://www.hormonerestoration.com/Thyroid.html
My home computer is crashed - I would have had a ton of articles for you. You can google up - Cytomel - and Free T3.
That will give you alot of information