“EPR and Optical Studies of Cr (III) Ions Doped NaCaAlPO F Nano Phosphor 4 3”, Int. J. Curr. Eng. Technol., vol. 1, no. 2.Special Issue, pp. 259–264, Feb. 2014, Accessed: Apr. 30, 2026. [Online]. Available: https://ijcet.evegenis.org/index.php/ijcet/article/view/3648