After publication of *On Computing the Complex Passivity Radius*
in CDC-ECC 2005, we discovered that we had overlooked two important
references

- T-S Hu and L Qiu,
**Complex and Real Performance Radii and their Computation**,*International Journal of Robust and Nonlinear Control*7, p.187-209, 1997 - T-S Hu and L Qiu,
**On Structured Perturbation of Hermitian Matrices**,*Linear Algebra Appl.*275-276, pp.287-314, 1998.