1. [B-G-K1] Bart, H., Gohberg, I., and Kaashoek, M.A.: Minimal Factorization of Matrix and Operator Functions, Birkhäuser, 1979.
2. [B-G-K2] Bart, H., Gohberg, I. and Kaashoek, M.A.: Wiener-Hopf factorization of analytic operator functions and realization, to appear.
3. [B-H1] Ball, J.A., and Helton, J.W.: A Beurling-Lax theorem for the Lie group U(m,n) which contains most classical interpolation theory, J. Operator Theory, 9(1983), 107?142.
4. [B-H2] Ball, J.A., and Helton, J.W.: Factorization results related to shifts in an indefinite metric, Integral Equations and Operator Theory, 5(1982), 632?658.
5. [B-H3] Ball, J.A., and Helton, J.W.: Beurling-Lax representations using classical Lie groups with many applications III: groups preserving forms, preprint.