The ‘Thyroid Protocol’ by Life Extensions Foundation may be found on their website.

Excellent  information on thyroid health can be found at the website 'Thyroid-Info'.

An article on 'Thyroid' can be found at Women's Health Connection.

An abstract of The New England Journal of Medicine article compares T4 alone with the combination of T3 & T4.

For information on USP (Natural) Thyroid you may go to 'Armour Thyroid's' website.