1. A method of generating a document clustering system, comprising: identifying entities in each document in a set of documents; obtaining association rules, corresponding to an initial set of documents, based on co-occurrences of the entities in the initial set of documents, each of the association rules identifying one or more entities that co-occur with other entities in the initial set of documents with a frequency that meets a threshold; and assigning the documents to a first set of clusters, based on the association rules derived from the initial set of documents.