Other
Melissa Kaplan: Reptile Skin Basis
A good introduction to the skin of reptiles. Describes some of the general characteristics of the scales. Information on various diseases is included. Also links to many related articles are listed.
University of California
Ucmp: The Tyrant Lizards: The Tyrannosauridae
This site from the University of California provides basic information on T. rex with links to related material great for a quick introduction.