Works citing   [J. Spectr. Theory 7 (2017), 659-697]

1. M. Znojil:
   Admissible perturbations and false instabilities in PT-symmetric quantum systems,
   Phys. Rev. A 97 (2018), 032114.
   
   
2. P. V. Hai and M. Putinar:
   Complex symmetric differential operators on Fock space,
   J. Differential Equations 265 (2018), 4213-4250.
   
   
3. O. I. Ibrogimov and F. Stampach:
   Spectral Enclosures for Non-self-adjoint Discrete Schrodinger Operators,
   Integral Equations Operator Theory 91 (2019), UNSP 53.
   
   
4. A. Arifoski and P. Siegl:
   Pseudospectra of the damped wave equation with unbounded damping,
   SIAM J. Math. Anal. 52 (2020) 1343-1362.