Adiguzel, Ragip, et al. “Synthesis and Characterization of Ni(II) and Cd(II) Complexes of 4-(4-Nitrophenylazo)- 1H-Pyrazole-3,5-Diamine and 4-(4-Methylphenylazo)-1H-Pyrazole-3,5-Diamine”. Asian Journal of Chemistry, vol. 23, no. 6, Mar. 2011, pp. 2795-00, https://asianpubs.org/index.php/ajchem/article/view/10438.