RT Journal Article SR Electronic T1 New US guidelines for research on human embryos JF Canadian Medical Association Journal JO CMAJ FD Canadian Medical Association SP 1672 OP 1672-a DO 10.1503/cmaj.050641 VO 172 IS 13 A1 Tim Lougheed YR 2005 UL http://www.cmaj.ca/content/172/13/1672.2.abstract