RT Journal Article SR Electronic T1 Neural tube defects JF Canadian Medical Association Journal JO CMAJ FD Canadian Medical Association SP 157 OP 158 DO 10.1503/cmaj.1041540 VO 172 IS 2 A1 J.A. Chris Delaney YR 2005 UL http://www.cmaj.ca/content/172/2/157.4.abstract