  The general parameterization of the quark-quark correlation function for a
spin-1/2 hadron is considered. The presence of the Wilson line ensuring color
gauge invariance of the correlator induces structures that were not given
explicitly in the existing literature. In particular, the general form of the
transverse momentum dependent correlator entering various hard scattering
processes is derived. In this case two new time-reversal odd parton
distributions appear at the twist-3 level.
