Deeba, Farah, et al. “Synthesis and Biological Evaluation of N’-(2-Hydroxybenzylidene)-1-Ethyl-1,4-Dihydro-7-Methyl-4-Oxo-1,8-Naphthyridine-3-Carbohydrazide and Its Complexes With Cu(II), Ni(II), Zn(II) and Fe(III)”. Asian Journal of Chemistry, vol. 25, no. 15, Sept. 2013, pp. 8351-4, doi:10.14233/ajchem.2013.14738.