  We investigate the spectral properties of Sturm-Liouville operators with
measure potentials. We obtain two-sided estimates for the spectral distribution
function of the eigenvalues. As a corollary, we derive a criterion for the
discreteness of the spectrum and a criterion for the membership of the
resolvents to Schatten classes. We give two side estimates for the lower bound
of the essential spectrum. Our main tool in achieving this is Otelbaev's
function.
