1. T.Ya. Azizov, P. Jonas, On Locally Definitizable Matrix Functions, Preprint 21-2005, Institute of Mathematics, Technische Universität Berlin.
2. J. Behrndt, P. Jonas, On Compact Perturbations of Locally Definitizable Selfadjoint Relations in Krein Spaces, Integral Equations Operator Theory 52 (2005), 17–44.
3. J. Behrndt, P. Jonas, Boundary Value Problems with Local Generalized Nevanlinna Functions in the Boundary Condition, to appear in Integral Equations Operator Theory.
4. V.A. Derkach, On Weyl Function and Generalized Resolvents of a Hermitian Operator in a Krein Space. Integral Equations Operator Theory 23 (1995), 387–415.
5. V.A. Derkach, On Generalized Resolvents of Hermitian Relations in Krein Spaces. J. Math. Sci. (New York) 97 (1999), 4420–4460.