WASET
    M. H. M. Rashid,  Stability of Property (gm) under Perturbation and Spectral Properties Type Weyl Theorems.   journal   = {International Journal of Physical and Mathematical Sciences}, [online]. World Academy of Science, Engineering and Technology.
    January 2019, vol. 146(2). 34 - 39
    [viewed 27 April 2024]. Available from: https://publications.waset.org/pdf/10010032.