Kazuyuki Amano Akira Maruoka On Optimal Merging Networks. 152-161 http://springerlink.metapress.com/openurl.asp?genre=article&issn=0302-9743&volume=2747&spage=152 2003 conf/mfcs/2003 MFCS db/conf/mfcs/mfcs2003.html#AmanoM03