@ARTICLE{
author={Kovacic Ivana N,Brennan Michael J,Lineton Benjamin},
year={2009},
title={Effect of a static force on the dynamic behaviour of a harmonically excited quasi-zero stiffness system},
journal={JOURNAL OF SOUND AND VIBRATION},
volume={325},
number={4-5},
pages={870-883},
document_type={Article},
} 

@ARTICLE{
author={Kovacic Ivana N,Brennan Michael J,Lineton Benjamin},
year={2008},
title={On the resonance response of an asymmetric Duffing oscillator},
journal={INTERNATIONAL JOURNAL OF NON-LINEAR MECHANICS},
volume={43},
number={9},
pages={858-867},
document_type={Article},
}