In one implementation, a computer-implemented method includes receiving a request to access an electronic document collection that integrates a plurality of electronic sub-documents that are each of one of a plurality of defined document types. The method also includes retrieving information that is associated with the document collection, wherein the retrieved information identifies a first sub-document of the plurality of sub-documents using a first non-address identifier, and identifying a first software application that is configured to provide access to the first sub-document. The method additionally includes initiating a first connection with a first server that causes execution of the identified first software application and that, using the first non-address identifier, provides access to the first sub-document. The method further includes integrating access to the first sub-document into the document collection through the initiated first connection with the first server that causes execution of the first software application.