How Stuff Works: Atomic Clock:
Concise history, background, definitions and operational information
regarding atomic clocks.
http://www.howstuffworks.com/atomic-clock.htm
How Stuff Works: Pendulum Clock:
Concise description using drawings and animation to show the
operation of a pendulum clock.
http://www.howstuffworks.com/clock.htm
Doug's Atomic Clocks:
Details on Doug Hogarth's experiments with his atomic clock.
http://www.niceties.com/atomic.html
