@incollection{TiB:99,
   author    = {A. L. Tits and V. Balakrishnan},
   title     = {Phase-sensitive structured singular value},
   booktitle = {Open Problems in Mathematical Systems and Control Theory},
   chapter   = {42},
   year      = {1999},
   editor    = {V. D. Blondel and E. D. Sontag and M. Vidyasagar and J. C. Willems},
   publisher = {Springer Verlag},
   address   = {London}
}