Hawking, Stephen. On the Shoulders of Giants the Great Works of Physics and Astronomy. Philadelphia: Running Press, 2002.
"Johannes Kepler: The Laws of Planetary Motion". <http://csep10.phys.utk.edu/astr161/lect/history/kepler.html>
"Kepler's Supernova Remnant: NASA's Great Observatories
Provide a Detailed View of Kepler's Supernova Remnant". Harvard-Smithsonian
Center for Astrophysics.
Aug 30 2006. <http://chandra.harvard.edu/photo/2004/kepler/>
Serway, Raymond, and John Jewett. Physics for
Scientists and Engineers 6th Ed. Belmont: Brooks/Cole-Thomspon
Learning, 2004.