1. Barmish, B.R.: New Tools for Robustness of Linear Systems. Macmillan, New York (1994)
2. Tesi, A., Vicino, A., Villoresi, F.: Robust Stability of Spherical Plants with Unstructured Uncertainty. In: Proceedings of the American Control Conference, Seattle, Washington, USA (1995)
3. Polyak, B.T., Shcherbakov, P.S.: Random Spherical Uncertainty in Estimation and Robustness. In: Proceedings of the 39th IEEE Conference on Decision and Control, Sydney, Australia (2000)
4. Chen, J., Niculescu, S.-I., Fu, P.: Robust Stability of Quasi-Polynomials: Frequency-Sweeping Conditions and Vertex Tests. IEEE Transactions on Automatic Control 53(5), 1219–1234 (2008)
5. Hurák, Z., Šebek, M.: New Tools for Spherical Uncertain Systems in Polynomial Toolbox for Matlab. In: Proceedings of the Technical Computing Prague 2000, Prague, Czech Republic (2000)