RT Journal Article SR Electronic T1 WHO mulls phase out of vaccine linked to polio outbreaks JF Canadian Medical Association Journal JO CMAJ FD Canadian Medical Association SP cmaj.109-4027 DO 10.1503/cmaj.109-4027 A1 Vogel, Lauren YR 2011 UL http://www.cmaj.ca/content/early/2011/11/14/cmaj.109-4027.abstract AB