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We show that certain classes of operator valued holomorphic functions that possess symmetry properties with respect to complex conjugation admit realisations as generalised resolvents of selfadjoint bounded operators in Krein spaces. This result, although is not the most general of this type, establishes a deep connection between operator valued holomorphic functions and operator theory, on one hand, and on the other hand, it motivates once more the interest for the spectral theory of selfadjoint operators in indefinite inner product spaces.