The upper limit of a parameter for a two-stroke oscillator to have a stable limit cycle

A type of Lienard's equation x + mu f(x)x + x = 0, where f(x) is not an even function of x, is Studied by Le Corbeiller as a model of various biological oscillations, such as breathing, and called two-stroke oscillators. A distinctive feature of this type of oscillators is that the parameter mu has the upper limit mu(0) for the oscillator to have some stable limit cycle. Phis paper gives a numerical method for calculating this upper limit mu(0).