@article{
        BoB:90,
        author= {S.~Boyd and V.~Balakrishnan},
        title= {A regularity result for the singular values of 
a transfer matrix and a quadratically convergent algorithm for 
computing its {${\bf L}_{\infty}$}-norm},
        journal= {Systems & Control Letters},
        volume= {15},
        pages={1-7},
        year= {1990}
        }