Mansori, Ghobad, and Saeid Asadpour. “Simultaneous Spectrofluorometric Determination of Phenylalanine and Tryptophane Using Rank Annihilation Factor Analysis”. Asian Journal of Chemistry, vol. 23, no. 1, Sept. 2010, pp. 268-72, https://asianpubs.org/index.php/ajchem/article/view/10125.