RAJENDRAN, G., and K.G. USHA DEVI. “Synthesis and Spectral Studies of Lanthanide(III) Complexes With 4-Methoxy- 4’-N,N-Dimethylaminodiphenyl Azomethine and Diphenyl Sulfoxide”. Asian Journal of Chemistry, vol. 19, no. 1, Mar. 2010, pp. 223-7, https://asianpubs.org/index.php/ajchem/article/view/20440.