Sarhan, B. M., 		Hamdan, T.A., AND 		Naema, B. Z..
" Synthesis and Characterization of Some mixed-Ligand  Complexes Containing N-acetyl Tryptophan and  (2, 2′-bipyridine) with Some Metal Salts" <em>Ibn AL- Haitham Journal For Pure and Applied Sciences</em> [Online], Volume 25 Number 3 (8 May 2017)