Tandon, S. P., M. P. Bhutra, and Anup Gupta. “Absorption Spectra of Ternary Complexes of Rare Earths”. Rev. Téc. Fac. Ing. Univ. Zulia 7, no. 2 (1). Accessed December 5, 2025. http://www.produccioncientificaluz.org/index.php/tecnica/article/view/5125.