title: qursed : querying and reporting semistructured data. authors: yannis papakonstantinou , michalis petropoulos , vasilis vassalos. venue: sigmod conference. year: 2002
title: semistructured and structured data in the web : going back and forth. authors: paolo atzeni , giansalvatore mecca , paolo merialdo. venue: acm sigmod record. year: 1997