TY - JOUR T1 - Spheres of influence JF - Canadian Medical Association Journal JO - CMAJ SP - 209 LP - 210 DO - 10.1503/cmaj.050962 VL - 174 IS - 2 AU - Normand Carrey Y1 - 2006/01/17 UR - http://www.cmaj.ca/content/174/2/209.abstract ER -