B.R. Potgieter and  G. Venter,  Experimental Modal Analysis and Model Validation of Antenna Structures.   journal   = {International Journal of Mechanical and Mechatronics Engineering}, [online]. World Academy of Science, Engineering and Technology.
    November 2009, vol. 35(11). 1380 - 1384
    [viewed 17 April 2021]. Available from: https://publications.waset.org/pdf/11898.