Category 
Title and Description 
Lead Author 
Place of Publication 
Introduction 
From Sundials to Atomic Clocks: Understanding Time and Frequency
Originally published in 1977, this fulllength book provides a comprehensive, easytounderstand introduction to the field of time and frequency. Readers of nearly all ages and educational backgrounds should find it enjoyable. 306 pages. 
Jespersen 
NIST Monograph 155, 1999 
NIST Time Signals 
NIST Time and Frequency Services
An illustrated, comprehensive overview that describes NIST Radio Stations WWVB, WWV, and WWVH work, and how you can use them. The NIST computer time and frequency calibration services are also briefly discussed. 80 pages. 
Lombardi 
NIST Special Publication 432, 2002 

How Accurate is a Radio Controlled Clock?
A detailed discussion of the accuracy of WWVB radio controlled clocks. It reviews the factors that limit the accuracy of a radiocontrolled clock, including the path delay between the radio station and the clock, how accurately the clock synchronizes with the signal, and how accurately the clock keeps time between synchronizations. 4 pages. 
Lombardi 
The Horological Journal, March 2010 

WWVB Radio Controlled Clocks: Recommended Practices for Manufacturers and Consumers
A booklet containing recommended practices for WWVB radio controlled clock manufacturers, plus tips for consumers attempting to troubleshoot reception problems. 64 pages. 
Lombardi 
NIST Special Publication 96014, 2009 

Radio Controlled Wristwatches
A general interest article about the various types of radio controlled wristwatches. 5 pages. 
Lombardi 
The Horological Journal, May 2006 

Radio Controlled Clocks
A discussion of the history of radio controlled clocks, how they work, and the types of radio signals that control them. 18 pages. 
Lombardi 
2003 NCSLI Conference 
Atomic Standards 
NIST Primary Frequency Standards and the Realization of the SI Second
A detailed overview of the primary frequency standards at NIST that covers their history, design, and the theory of operation. Includes color photographs of all of the NIST primary cesium standards and an extensive list of references. 17 pages. 
Lombardi 
Measure: The Journal of Measurement Science, December 2007 

Standards of Time and Frequency at the Outset of the 21st Century
A nicely written overview that examines the first fifty years of microwave atomic clocks, and the ongoing progression towards optical standards. 7 pages. 
Diddams 
Science, November 2004 

Time Measurement at the Millennium
A discussion of recent developments in atomic timekeeping, written for the NIST centennial in 2001. Winner of the 2001 NIST Condon award for best paper. 6 pages. 
Bergquist 
Physics Today, March 2001 

Primary Atomic Frequency Standards at NIST
A discussion of the primary atomic frequency standards that have been developed at NIST. Includes some historical information, but is mainly about recent, current, and possible future standards. 17 pages. 
Sullivan 
NIST Journal of Research, JanuaryFebruary 2001 

Accurate Measurement of Time
Excellent general interest article about atomic timekeeping. 8 pages. 
Itano 
Scientific American, July 1993 
Computer Timekeeping 
NIST Computer Time Services: Internet Time Service (ITS), Automated Computer Time Service (ACTS), and time.gov Web Sites
A thorough discussion of how the NIST computer time services work. 79 pages. 
Levine 
NIST Special Publication 25059, May 2002 
GPS Time Transfer 
Time and Frequency Dissemination: Advances in GPS Transfer Techniques
An overview of the various ways GPS is used for time and frequency applications. Written by authors from NIST and the United States Naval Observatory (USNO). 7 pages. 
Parker 
GPS World, November 2004 

The Use of GPS Disciplined Oscillators as Primary Frequency Standards for Calibration and Metrology Laboratories
A discussion of the use of GPS disciplined oscillators (GPSDOs) in calibration laboratories. It discusses how GPSDOs work, how measurement traceability can be established with a GPSDO, and how their performance can vary significantly from model to model. 10 pages. 
Lombardi 
Measure: The Journal of Measurement Science, September 2008. 

Time and frequency distribution using satellites
A comprehensive discussion of how time and frequency information is distributed through GPS and other satellite systems. 46 pages. 
Levine 
Reports on Progress in Physics, July 2002 

Time and Frequency Measurements using the Global Positioning System (GPS)
An overview of the various types of GPS measurements, including the oneway, twoway, and carrier phase techniques. Includes a discussion of traceability. 8 pages. 
Lombardi 
Cal Lab Magazine, JulySeptember 2001 
History 
The Evolution of Time Measurement, Part 1: Celestial, Flow, and Mechanical Clocks
The Evolution of Time Measurement, Part 2: Quartz Clocks
The Evolution of Time Measurement, Part 3: Atomic Clocks
The Evolution of Time Measurement, Part 4: The Atomic Second
The Evolution of Time Measurement, Part 5: Radio Controlled Clocks
A fivepart series of short articles about the history of clocks and timekeeping. The articles range from 4 to 8 pages in length, and attempt to focus on the most significant events in the history of timekeeping, by discussing both the advances in technology and the people involved. Illustrated with color photos. 
Lombardi 
IEEE Instrumentation and Measurement Magazine, August 2011  April 2012 

Time and Frequency Measurement at NIST: The First 100 Years
A history of time and frequency activities at NIST, written for the NIST centennial in 2001. 14 pages. 
Sullivan 
2001 IEEE Frequency Control Symposium 
Metrology 
Characterization of Clocks and Oscillators
A collection of published papers assembled as a reference for those involved in characterizing and specifying highperformance clocks and oscillators. Includes extensive information about measurement techniques and data analysis. 352 pages. 
Sullivan 
NIST Technical Note 1337, 1990 

Time and Frequency Users Manual
A detailed, easytoread overview of time and frequency measurements. Includes information about quartz and atomic oscillators, and the various radio signals used as measurement references. Outdated in some areas, but still useful. 160 pages. 
Kamas 
NIST Special Publication 559, 1990 

Time and Frequency Measurement
A collection of classic time and frequency papers published by authors from NIST and elsewhere. Includes a comprehensive bibliography. 143 pages. 
Hackman 
American Associations of Physics Teachers Publication, 1996 

Introduction to time and frequency metrology
An introduction to the principles and concepts of time and frequency metrology. 30 pages. 
Levine 
Review of Scientific Instruments, June 1999 

Fundamentals of Time and Frequency
An overview of time and frequency metrology intended for nonspecialists. 18 pages. 
Lombardi 
The Mechatronics Handbook, 2001 

Legal and Technical Measurement Requirements for Time and Frequency
An overview of time and frequency requirements for various technologies and applications. 10 pages. 
Lombardi 
Measure: The Journal of Measurement Science, September 2006 

Handbook of Frequency Stability Analysis
An excellent reference source that covers the statistics used for the analysis of time and frequency data. It also provides a brief overview of measurement techniques. 136 pages. 
Riley 
NIST Special Publication 1065, 2008 

Stopwatch and Timer Calibrations
A NIST recommended practice guide that describes several ways to calibrate stopwatches and timers. 82 pages. 
Gust 
NIST Special Publication 96012, 2009 