RT Journal Article SR Electronic T1 Opioid prescribing challenges doctors JF Canadian Medical Association Journal JO CMAJ FD Canadian Medical Association SP E143 OP E144 DO 10.1503/cmaj.109-3033 VO 181 IS 8 A1 Ann Silversides YR 2009 UL http://www.cmaj.ca/content/181/8/E143.abstract