  Using group theoretical methods, we enumerate possible chiral representations
in which hadron interpolating currents can be classified. We give simple
examples of currents in each representation, some of which are well known. The
classification enables one to find relations among current vacuum correlators
in a chirally and/or axial U(1) symmetric phase of QCD in a straightforward
way. Besides recovering many well-known relations among two-point correlation
functions, a number of novel relations are found.
