Radoslav Fulek Hongmei He Ondrej Sýkora Imrich Vrto Outerplanar Crossing Numbers of 3-Row Meshes, Halin Graphs and Complete p-Partite Graphs. 376-379 http://springerlink.metapress.com/openurl.asp?genre=article&issn=0302-9743&volume=3381&spage=376 2005 conf/sofsem/2005 SOFSEM db/conf/sofsem/sofsem2005.html#FulekHSV05