  The blocking effect caused by the odd particle on the pairing properties of
systems with odd number of fermions at finite temperature interacting via the
monopole pairing force is studied within several approximations. The results
are compared with the predictions obtained by using the exact solutions of the
pairing Hamiltonian. The comparison favors the approximation with the odd
particle occupying the top level, which is the closest to the Fermi surface and
whose occupation number decreases with increasing temperature.
