Asaad M. Jassim Al-Hindawi, D., and S. M. Al- Ali. “Theoretical and Experimental Results of Substrate Effects on Microstrip Power Divider Designs”. Al-Rafidain Engineering Journal (AREJ), vol. 19, no. 6, Dec. 2011, pp. 15-25, doi:10.33899/rengj.2011.26603.