1. G. Duffing, Erzwungene Schwingung bei veränderlicher Eigenfrequenz und ihre technische Bedeutung (Vieweg, Braunschweig 1918)
2. Y. Ueda, Randomly transitional phenomena in the system governed by Duffing’s equation, J. Stat. Phys. 20 (1979) 181
3. Y. Ueda, Steady motions exhibited by Duffing’s equation: A picture book of regular and chaotic motions, in: H. Bai-Lin, D. H. Feng, and J.-M. Yuan, editors, New Approaches to Nonlinear Problems, SIAM, Philadelphia 1980
4. F. C. Moon, Chaotic Vibrations (J. Wiley, New York 1987)
5. N. Minorsky, Nonlinear Oscillations (Van Nostrand, New York 1962)