  The problem of crossover from BCS to Bose-Einstein condensation has recently
attracted considerable interest owing to the discovery of high-$T_{\rm c}$
cuprates. Their short coherence length, $\xi$, places these materials in the
interesting region between BCS and Bose-Einstein condensation. In the paper of
F. Pistolesi and G.C. Strinati (Phys. Rev. B {\bf 49}, 6356 (1994)), the
Nozi\`eres and Schmitt-Rink approach (NSR) is taken, which is valid for the
weak coupling regime. They derive a relation between $T_{\rm c}$ and $T_{\rm
F}$, which they insist is valid for any coupling strength. We present arguments
that their assumptions are incorrect by using our fully self-consistent
T-matrix formalism in two dimensions, and show that the NSR approach produces
unphysical results in this case.
