Rezaeivala, M. and Daftari, S. (2014) “Ab initio calculations of 13C NMR chemical shielding in some N4O2, N4S2 and N6 Schiff base ligands containing piperazine moiety”, European Journal of Chemistry, 5(2), pp. 343–350. doi: 10.5155/eurjchem.5.2.343-350.959.