R.  Uzdin, Friedland, L. , and Gat, O. . 2014. ?First-Harmonic Approximation In Nonlinear Chirped-Driven Oscillators?. Physical Review E - Statistical, Nonlinear, And Soft Matter Physics, 89, Pp. 012902. http://search.ebscohost.com/login.aspx?direct=true&db=edselc&AN=edselc.2-52.0-84894567017&site=eds-live.