Yang, Yu-Hua, et al. “Synthesis and Structure Characterization of Copper(II) Complexes With 5,5’-Dihydroxy-2,2’-[ethylenedioxybis(nitrilomethylidyne)]diphenol”. Asian Journal of Chemistry, vol. 25, no. 16, Oct. 2013, pp. 9359-61, doi:10.14233/ajchem.2013.15626.