Deok-Soo Kim Kwangseok Yu Youngsong Cho Donguk Kim Chee-Keng Yap Shortest Paths for Disc Obstacles. 62-70 http://springerlink.metapress.com/openurl.asp?genre=article&issn=0302-9743&volume=3045&spage=62 2004 conf/iccsa/2004-3 ICCSA (3) db/conf/iccsa/iccsa2004-3.html#KimYCKY04