Duffing oscillator
- Dynamical symmetry breaking and chaos in Duffing's equation, C. Olson and M. Olsson, AJP 59 (10) 907-911, 1991
- Chaos in the motion of an inverted pendulum: An undergraduate laboratory experiment, B. Duchesne et al, AJP 59 (11) 987-992, 1991
- A mechanical Duffing oscillator for the undergraduate laboratory, J. Berger and G. Nunes, AJP 65 (9) 841--846, 1997