1. Amniocentesis for prenatal diagnosis;Verp;Clin Obstet Gynecol,1981
2. Rates of chromosome abnormalities at different maternal ages;Hook;Obstet Gynecol,1981
3. An assessment of the hazards of amniocentesis;Working party on amniocentesis;Br J Obstet Gynaecol,1978
4. Mid-trimester amniocentesis for prenatal diagnosis Safety and accuracy;NICHD National Registry for amniocentesis study group;JAMA,1976
5. Diagnosis of genetic disease by amniocentesis during the second trimester of pregnancy. Report no 5;Medical Research Council of Canada,1977