Manuel Abellanas Prosenjit Bose Alfredo García Olaverri Ferran Hurtado Pedro A. Ramos Eduardo Rivera-Campo Javier Tejel On Local Transformations in Plane Geometric Graphs Embedded on Small Grids. 22-31 http://springerlink.metapress.com/openurl.asp?genre=article&issn=0302-9743&volume=3045&spage=22 2004 conf/iccsa/2004-3 ICCSA (3) db/conf/iccsa/iccsa2004-3.html#AbellanasBOHRRT04