Zhengsheng Wang and  Xiangyong Ji and  Yong Du,  The Projection Methods for Computing the Pseudospectra of Large Scale Matrices.   journal   = {International Journal of Mathematical and Computational Sciences}, [online]. World Academy of Science, Engineering and Technology.
    January 2010, vol. 37(1). 69 - 73
    [viewed 10 May 2024]. Available from: https://publications.waset.org/pdf/5844.