  Using the field-theoretical methods we studied the evolution from BCS
description of a non-Fermi superconductor to that of Bose-Einstein condensation
(BEC) in one loop approximation. We showed that the repulsive interaction
between composite bosons is determined by the exponent $\alpha$ of the Anderson
propagator in a two dimensional model. For $\a\neq 0$ the crossover is also
continous and for $\a=0$ we obtain the case of the Fermi liquid.
