K. Agarwal, Suresh, and Subhash Chand. “Synthesis and Characterization of Ternary Hetero Chelates of La(III), Pr(III), Nd(III) and Sm(III)”. Asian Journal of Chemistry, vol. 11, no. 3, Mar. 2010, pp. 975-8, https://asianpubs.org/index.php/ajchem/article/view/23407.