  We derive the time-independent Gross-Pitaevskii equation at zero temperature
for condensed bosons, which form as bound-fermion pairs when the mutual
fermionic attractive interaction is sufficiently strong, from the
strong-coupling limit of the Bogoliubov-de Gennes equations that describe
superfluid fermions in the presence of an external potential. Three-body
corrections to the Gross-Pitaevskii equation are also obtained by our approach.
Our results are relevant to the recent advances with ultracold fermionic atoms
in a trap.
