@ARTICLE{
author={Kovacic Ivana N,Mickens Ronald E},
year={2015},
title={Design of nonlinear isochronous oscillators},
journal={NONLINEAR DYNAMICS},
volume={81},
number={1-2},
pages={53-61},
document_type={Article},
} 

@ARTICLE{
author={Kovacic Ivana N,Mickens Ronald E},
year={2012},
title={A generalized van der Pol type oscillator: Investigation of the properties of its limit cycle},
journal={MATHEMATICAL AND COMPUTER MODELLING},
volume={55},
number={3-4},
pages={645-653},
document_type={Article},
}