Ascent, Descent, Nullity and Defect, a Note on a Paper by A.E. Taylor M.A. Kaashoek — 1967 Mathematische Annalen
Relative Inverses of Meromorphic Operator Functions and Associated Holomorphic Projection Function. M.A. Kaashoek; H. Bart; D.C. Lay — 1975 Mathematische Annalen
Common multiples of operator polynomials with analytic coefficients. M.A. Kaashoek; I. Goberg; F. Schagen — 1978 Manuscripta mathematica