Singh, Lakshman, et al. “Structure and Bonding of Some Newly Syntheisised Complexes of Lanthanide(III) Complexes of 4[N-(p-Dimethylaminobenzalidene) Amino] Antipyrine Thiosemicarbazone”. Asian Journal of Chemistry, vol. 11, no. 4, Mar. 2010, pp. 1445-50, https://asianpubs.org/index.php/ajchem/article/view/23509.