1. LORD, RAYLEIGH, 1887, The Theory of Sound, 1, New York, Dover
2. Natural frequencies of rings that depart from perfect axial symmetry;ALLAEI;Journal of Sound and Vibration,1986
3. C. H. J. FOX, 1988, Proceedings of DGON Symposium on Gyro Technology, Stuttgart, Vibrating cylinder rate gyro: theory of operation and error analysis
4. I. HOPKIN, 1997, Proceedings of DGON Symposium on Gyro Technology, Stuttgart, Performance and design of a silicon micro-machined gyro
5. A theory of imperfection for elastic bodies of revolution;TOBIAS;Engineering,1951