Abstract: The invention relates to a method and a system for detecting a similarity of documents. The similarity of documents is detected with the help of an analysis of citations in one or more citation document(s), wherein the distance between the individual citations is used as criterion of the analysis. On the basis of the determined distance between two citations, respectively, a similarity value is determined, which is characteristic of the cited documents. A small distance between two citations leads to a high similarity of the cited documents. In case of several citations with regard to documents from several citation documents, the similarity values for the citation pairs from the individual citation documents are used for determining a final similarity value.