  Inhomogeneous solutions of the gap equation in the mean field approach to
Nambu-Jona-Lasinio model are studied. An approximate Ginzburg-Landau-like gap
equation is obtained and the domain wall solution is found. Binding of fermions
to the domain wall is demonstrated. Compact domain wall with bound fermions is
studied and stabilisation by fermion pressure is demonstrated which opens a
possibility for existence of "soap bubble" hadronic states.
