Traditional approaches to versioning semistructured information are edit-based, i.e., subsequent document versions are represented by using edit scripts. This paper proposes a reference-based version management scheme that preserves the logical structure of the evolving document through the use of object references. By preserving the document structure among versions the new scheme facilitates more efficient query support. In particular, we examine queries involving projections and selections on the document versions, as well as queries on the document evolution history. Moreover, we show that the proposed scheme provides an effective representation of multiversioned XML documents, both at the transport and exchange levels. In fact, with the reference-based scheme, a document's history can also be viewed and processed as yet another XML document. Furthermore, we demonstrate the effectiveness of the new scheme at the storage level. In particular, the scheme is enhanced with a usefulness-based page management policy that extends and adapts techniques used in transaction-time databases to ensure efficient clustering of information among versions. An extensive comparison of the reference-based versioning against representations used in temporal databases and persistent object managers depicts the performance advantages of the new approach. Finally it should be noted that reference-based versioning is applicable to other kinds of semistructured information (besides XML documents), and can be used to replace traditional version control schemes, such as the edit-based RCS and the timestamp-based SCCS.