Integration of Composite Objects into Relational Query Processing: The SQL/XNF Approach.

Bernhard Mitschang Hamid Pirahesh Integration of Composite Objects into Relational Query Processing: The SQL/XNF Approach. 35-62 Query Processing for Advanced Database Systems, Dagstuhl Morgan Kaufmann 1991 db/books/collections/dagstuhl91.html#MitschangP91