The local theory of regular matrix polynomials / I. Gohberg, M.A. Kaashoek, F. van SchagenOperator blocks and quadruples of subspaces : classification and the eigenvalue completion problem / I. Gohberg, M.A. Kaashoek, F. van SchagenSzegö-Kac-Achiezer formulas in terms of realizations of the symbol / I. Gohberg, M.A. Kaashoek, F. van Schagen