In this paper we address the problem of link repair in bibliographic knowledge bases. In the context of the SudocAD project, a decision support system (DSS) is being developed, aiming to assist librarians when adding new bibliographic records. The DSS makes the assumption that existing data in the system contains no linkage errors. We lift this assumption and detail a method that allows for link validation. Our method is based on two partitioning semantics which are formally introduced and evaluated on a sample of real data.