21. The computer-readable medium of claim 20 , wherein identifying the priority associated with the sources of each document version of the plurality of different document versions comprises: performing a lookup in a memory to identify the priority associated with each respective source of each respective document version of the plurality of different document versions.
20. The computer-readable medium of claim 17 , wherein applying the priority rule comprises: identifying a priority associated with the source of each document version of the plurality of different document versions; and determining the priority value for each document version of the plurality of different document versions based on the identified priority associated with the source of each document version of the plurality of document versions.