S Lu, Y Guo, L Chen - Nonlinear Analysis: Real World Applications, 2019 - Elsevier
In this paper, the problem of periodic solutions is studied for Liénard equations with
anindefinite singularity x′′(t)+ f (x (t)) x′(t)+ φ (t) xm (t)− α (t) x μ (t)= 0, where f:(0,+∞)→ R …