Altun, O. and Bilcen, S. 2012. Spectrophotometric investigation of DL-tryptophan in the presence of Ni(II) or Co(II) ions. European Journal of Chemistry. 3, 4 (Dec. 2012), 411–415. DOI:https://doi.org/10.5155/eurjchem.3.4.411-415.482.