1. Constructing a unitary Hessenberg matrix from spectral data;Ammar,1991
2. Schur flow for orthogonal Hessenberg matrices;Ammar,1994
3. On the eigenproblem for orthogonal matrices;Ammar,1986
4. Beiträge zur numerischen Behandlung des unitären Eigenwertproblems;Bohnhorst,1993
5. On the perturbation theory for unitary eigenvalue problems;Bohnhorst;SIAM J. Matrix Anal. Appl.,2000