Rezaeivala, Majid, and Sam Daftari. 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):343-50. https://doi.org/10.5155/eurjchem.5.2.343-350.959.