1
by Helfand, Mark
Published 2007
Oregon Health & Science University

2
by Chou, Roger, Helfand, Mark, Peterson, Kim, Dana, Tracy
Published 2006
Agency for Healthcare Research and Quality (US)

5
by Chou, Roger, Helfand, Mark, Peterson, Kim, Dana, Tracy
Published 2006
Agency for Healthcare Research and Quality (US)

6
by Helfand, Mark
Published 2007
Oregon Health & Science University