Publications and References
Frequency Standards Laboratory
Also see:
How Does it Work?
Trapped Ion Frequency Standards
Photonics
Ultra-stable Microwave Oscillators
Noise Analysis and Statistics
Laser Cooled Atomic Physics
Frequency
Standards Laboratory Frequency
Standards Laboratory 
Trapped
Ion Frequency Standards 
Photonics
Ultra-stable
Microwave Oscillators
Noise
Analysis and Statistics 
Laser
Cooled Atomic Physics