M.
      L-infinity-norm computation for continuous-time descriptor
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  [4] Benner, P., Sima, V. and Voigt, M.
      Robust and efficient algorithms for L-infinity-norm
      computations for descriptor systems.
      7th IFAC Symposium on Robust Control Design (ROCOND'12),
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  [5] Benner, P., Sima, V. and Voigt, M.
      Algorithm 961: Fortran 77 subroutines for the solution of
   