RT Journal Article SR Electronic T1 Prevention of midline defects. JF Journal of Medical Genetics JO J Med Genet FD BMJ Publishing Group Ltd SP 473 OP 474 DO 10.1136/jmg.21.6.473-a VO 21 IS 6 A1 Walther, J U A1 Raeburn, J A YR 1984 UL http://jmg.bmj.com/content/21/6/473.2.abstract AB