1. Maternal age and births in the 1980's;Adams;JAMA,1982
2. Pregnancy in gravidas over age 35 years;Stein;Nurse Midwife,1983
3. Pregnancy outcomes in black women aged 35 and older;Grimes;Obstet ,Gynecol,1981
4. Pregnancy in women over forty;Horger;Obstet Gynecol,1979
5. Pregnancy and delivery in women aged 40 and over;Kajanoja;Obstet Gynecol,1978