Hiroyuki Kato Masatoshi Yoshikawa A model and queries for databases managing structured documents with object links. 29-44 2000 31 Systems and Computers in Japan 6 http://dx.doi.org/10.1002/(SICI)1520-684X(200006)31:6<29::AID-SCJ4>3.0.CO;2-0 db/journals/scjapan/scjapan31.html#KatoY00