Measurement techniques of piezoelectric, dielectric and electrostatic oscillators - Part 3: Frequency aging test methods (IEC 62884-3:2018); German version EN IEC 62884-3:2018— 15 стр.
Measurement techniques of piezoelectric, dielectric and electrostatic oscillators -- Part 4 : Short-term frequency stability test methods ((IEC 62884-4:2019) EN IEC 62884-4:2019) (english version)