@article{TBL:99,
   author    = {A. L. Tits and V. Balakrishnan and L. Lee},
   title     = {Robustness under Bounded Uncertainty with Phase
       Information},
   journal   = {IEEE Trans.\ Aut.\ Control},
   year      = 1999,
   month     = jan,
   volume    = {AC-44},
   number    = 1,
   pages     = {50-65}
}