TY - JOUR T1 - Fundamental problem with opioid trials for chronic pain JF - Canadian Medical Association Journal JO - CMAJ SP - 1307 LP - 1308 DO - 10.1503/cmaj.1060140 VL - 176 IS - 9 AU - Tushar Mehta Y1 - 2007/04/24 UR - http://www.cmaj.ca/content/176/9/1307.3.abstract ER -