Rayan, D. A., Y. H. Elbashar, and S. S. Moslem. “ESR and Magnetic Studies of Nickel Ions Doped P2O5–ZnO–Na2O Glassy System”. Revista Mexicana De Física, vol. 66, no. 5 Sept-Oct, Sept. 2020, pp. 580-4, doi:10.31349/RevMexFis.66.580.