@article{paperid:201192,
author = {Afsharnejad, Zahra},
title = {effect of nonlinear terms f (x,x) on harmonic oscillator},
journal = {Iranian Journal of Science and Technology-Transaction B: Engineering},
year = {2002},
month = {January},
issn = {1028-6284},
keywords = {periodic solutions; perturbation; nonlinear damping},
}