Reduction of the quasipotential equations to the Sturm-Liouville problems and the method of standardized equation

The comparison equation method (CEM) allowing to find solutions in the form of asymptotic series over reverse coupling constant degrees is formulated and applied to the quasipotential Sturm-Liouville problem in the momentum representation. The descrete energy spectrum at arbitrary binding energies is obtained with the help of this method. The problem with the Cramers substitution is discussed using a modified version of the quasipotential Sturm-Liouville problem as an example. This substitution is necessary if the initial equation cannot be exactly standardized