RT Journal Article SR Electronic T1 New outbreaks of polio: WHO issues travel warning JF Canadian Medical Association Journal JO CMAJ FD Canadian Medical Association SP 231 OP 231 DO 10.1503/cmaj.1041093 VO 171 IS 3 A1 Aleksandra MiĊĦak YR 2004 UL http://www.cmaj.ca/content/171/3/231.abstract