RT Journal Article SR Electronic T1 Rofecoxib (Vioxx) voluntarily withdrawn from market JF Canadian Medical Association Journal JO CMAJ FD Canadian Medical Association SP 1027 OP 1028 DO 10.1503/cmaj.1041606 VO 171 IS 9 A1 Sibbald, Barbara YR 2004 UL http://www.cmaj.ca/content/171/9/1027.abstract