@Article{Elabbasy2011,
author = "Elabbasy, E. M. and Elzeiny, Sh. R.",
title = "Oscillation theorems concerning non-linear differential equations of the second order",
journal = "Opuscula Math.",
year = "2011",
volume = "31",
number = "3",
pages = "373--391",
doi = "http://dx.doi.org/10.7494/OpMath.2011.31.3.373",
url = "http://dx.doi.org/10.7494/OpMath.2011.31.3.373",
abstract = "This paper concerns the oscillation of solutions of the differential eq. \[ \left[ r\left( t\right) \psi \left(x\left( t\right) \right) f\text{ }( \overset{\cdot }{x}(t))\right]^{\cdot }+q\left( t\right) \varphi (g\left( x\left( t\right) \right), r\left( t\right) \psi \left( x\left( t\right) \right) f(\overset{\cdot }{x}(t)))=0,\] where \(u\varphi \left( u,v\right) \gt 0\) for all \(u\neq 0\), \(xg\left( x\right) \gt 0\), \(xf\left( x\right)\gt 0\) for all \(x\neq 0\), \(\psi \left( x\right) \gt 0\) for all \(x\in \mathbb{R}\), \(r\left( t\right) \gt 0\) for \(t\geq t_{0}\gt 0\) and \(q\) is of arbitrary sign. Our results complement the results in [A.G. Kartsatos, On oscillation of nonlinear equations of second order, J. Math. Anal. Appl. 24 (1968), 665–668], and improve a number of existing oscillation criteria. Our main results are illustrated with examples.",
keywords = "second order, nonlinear, differential equations, oscillation",
issn = "1232-9274"
}