Shaaban, N. ., and S. . Nouraldin. “Determining the Mutual Interaction Factor for Phonon-Exciton in AgBr Crystal Doped With Copper”. Tishreen University Journal -Basic Sciences Series, vol. 41, no. 1, Jan. 2021, https://journal.tishreen.edu.sy/index.php/bassnc/article/view/7916.