The Ontario printed educational message (OPEM) trial to narrow the evidence-practice gap with respect to prescribing practices of general and family physicians: a cluster randomize... oleh Grimshaw Jeremy, Paterson Michael, Kelsall Diane, Hux Janet E, Zwarenstein Merrick, Davis Dave, Laupacis Andreas, Evans Michael, Austin Peter C, Slaughter Pamela M, Shiller Susan K, Croxford Ruth, Tu Karen