  We use the Density Matrix Renormalization Group technique to compute
correlation functions of the Z_3-chiral Potts quantum chain in the massive
regimes. Chains of up to 70 sites are used and a clear oscillatory behavior is
found. We also check the relation between the density matrix spectrum and the
Corner Transfer Matrix spectrum pointed out by Nishino and Okunishi, using
Baxter's low-temperature formulae for the chiral Potts Corner Transfer Matrix
eigenvalues. We find very good agreement.
