Gaur, Gajendra, B.P. Singh, and M.S. Kaurav. 2010. “Study of the Ternary 1:1:1 Ln(III)-CDTA-Phenyl Alanine Tyrosine Tryptophane Complexes”. Asian Journal of Chemistry 21 (2):1569-74. https://asianpubs.org/index.php/ajchem/article/view/18866.