1. An oscillation criterion for a class of ordinary differential equations;Kiguradze;Differentsial'nye Uravneniya,1992
2. Gregus M. & Gregus M. Jr, An oscillation criterion for nonlinear third order differential equations, to appear.
3. Some results in the theory of a third-order linear differential equation;Gregus;Ann. Polon. Math.,1983
4. An elementary derivation of a necessary and sufficient condition for non-oscillation of the solutions of a second order linear differential equation;Kondrat'ev;Uspehi Mat. Nauk,1957
5. Oscillation criteria for third-order linear differential equations;Rovder;Mat. Časopis,1975