RT Journal Article SR Electronic T1 Efficacy of pneumococcal polysaccharide vaccine JF Canadian Medical Association Journal JO CMAJ FD Canadian Medical Association SP 1134 OP 1135 DO 10.1503/cmaj.1090018 VO 180 IS 11 A1 Pippa Scott A1 Anke Huss A1 Andreas E. Stuck A1 Caroline Trotter A1 Matthias Egger YR 2009 UL http://www.cmaj.ca/content/180/11/1134.2.abstract