PROBLEM TO BE SOLVED: To enable computer-implemented content propagation for enhanced document retrieval. SOLUTION: Reference information directed to one or a plurality of documents is identified. The reference information is identified from one or a plurality of sources of data that are independent of a data source including the one or a plurality of documents. Metadata that are proximally located to the reference information are extracted from the one or a plurality of sources of data. Relevance between respective features of the metadata to contents of associated ones of the one or a plurality of documents is calculated. For each document of the one or a plurality of documents, associated portions of the metadata are indexed with the relevance of features from the respective portions into original contents of the document. The indexing preparing function generates one or a plurality of enhanced documents. COPYRIGHT: (C)2006,JPO&NCIPI