1. Ball, J.A. and Ran, A.C.M., Hankel norm approximation of a rational matrix function in terms of its realization, in Proceedings of 1985 Symposium on the Mathematical Theory of Networks and Systems (Stockholm), to appear.
2. Ball, J.A. and Ran, A.C.M., Optimal Hankel norm model reductions and Wiener-Hopf Factorization I: The canonical case, SIAM J. Control and Opt., to appear.
3. Bart, H.; Gohberg, I. and Kaashoek, M.A., Minimal Factorization of Matrix and Operator Functions, OT1 Birkhauser, Basel, 1979.
4. Bart, H.; Gohberg, I. and Kaashoek, M.A., The coupling method for solving integral equations, in Topics in Operator Theory Systems and Networks (ed. H. Dym and I. Gohberg), OT 12 Birkhauser, Basel, 1983, 39–73.
5. Bart, H.; Gohberg, I.; Kaashoek, M.A. and van Dooren, P., Factorization of transfer functions, SIAM J. Control and Opt. 18 (1980), 675–696.