1. Biezeno, C.B., Grammel, R.: Technische Dynamik. Springer, Heidelberg (1939)
2. Den Hartog, J.P.: Mechanical Vibration. McGraw-Hill Book Co., New York (1940)
3. Duncan, W.J., Collar, A.R.: Solution of Oscillation Problems by Matrices. Philos. Mag. 17, 866 (1934)
4. Goldstine, H.H., Goldstine, A.: The Electronic Numerical Integrator and Computer, ENIAC (1946); reprinted in The Origins of Digital Computers: Selected Papers, p. 359. Springer, Heidelberg
5. Hahn: Note sur la vitesse critique et la formule du Dunkerley, Schweiz. Bauztg., vol. 72, p. 191 (1918)