Oswego City School District
Regents Exam Prep Center: Theorems and Postulates for Geometry
Here is a partial list of theorems, postulates, and properties.
Dartmouth College
Dartmouth College: The Different Styles of Euclid and Copernicus
A history of the differences between Euclid's and Copernicus's methods of proving geometric ideas.
Other
Mathematical the Four Color Theorem and Computer Proof
This site describes the role of computer involvement in the four color map theorem.