1. Characterization of phase and frequency instabilities in precision frequency sources: Fifteen years of progress
2. CCIR Study Group VII, “Characterization of Frequency and Phase Noise,” Report No. 580-3, in Standard Frequencies and Time Signals, volume VII (annex) of Recommendations and Reports of the CCIR, pages 160–171 (International Telecommunication Union (ITU), Geneva, Switzerland, 1990).