Challal, M. , Labu, F. , Dehmas, M. , Azrar, A. (2011). 'Comparative Study of Three DGS Unit Shapes and Compact Microstrip Low-Pass and Band-Pass Filters Designs'. World Academy of Science, Engineering and Technology, Open Science Index 59, International Journal of Electronics and Communication Engineering, 5(11), 1486 - 1490.