Mostafa Ghayour and  Mohammad Sadegh Golabi,  Effect of Geometrical Parameters on Natural Frequencies of FGM Cylindrical shell with Holes Under Various Boundary Conditions.   journal   = {International Journal of Mechanical and Mechatronics Engineering}, [online]. World Academy of Science, Engineering and Technology.
    September 2011, vol. 57(9). 1751 - 1756
    [viewed 14 October 2019]. Available from: https://publications.waset.org/pdf/9102.