1. Parental origin of the extra chromosome in trisomy 21 revisited: DNA polymorphism analysis suggests that in 95% of cases the origin is maternal (abstract);Antonarakis;Am J Hum Genet,1990
2. Risk factors for congenital heart diseases in Alexandria, Egypt;Bassili;Eur J Epidemiol,2000
3. Geographic variations in possible risk factors for severe cardiac malformations;Cedergren;Acta Paediatr,2002
4. ACOG committee opinion. Advanced paternal age: risks to the fetus;Committee on Genetics;Int J Gynecol Obstet,1997
5. Paternal age and Down syndrome;Erickson;Am J Hum Genet,1979