  We study states in the superconducting gap induced by magnetic impurities
using self-consistent quantum Monte Carlo with maximum entropy and formally
exact analytic continuation methods. The magnetic impurity susceptibility has
different characteristics for $T_{0} \alt T_{c0}$ and $T_{0} \agt T_{c0}$
($T_{0}$: Kondo temperature, $T_{c0}$: superconducting transition temperature)
due to the crossover between a doublet and a singlet ground state. We
systematically study the location and the weight of the gap states and the gap
parameter as a function of $T_{0}/T_{c0}$ and the concentration of the
impurities.
