Teruhisa Hochin Hiroki Nomiya A Logical and Graphical Operation of a Graph-Based Data Model. 1079-1084 2009 ACIS-ICIS http://dx.doi.org/10.1109/ICIS.2009.130 conf/ACISicis/2009 db/conf/ACISicis/ACISicis2009.html#HochinN09