1. Demographic and medical consequences of the postponement of parenthood;Schmidt;Hum Reprod Update,2012
2. Delayed child-bearing;Johnson;J Obstet Gynaecol Can,2012
3. Delayed childbearing and the outcome of pregnancy;Berkowitz;N Engl J Med,1990
4. Mean age of mothers is on the rise: United States, 2000–2014;Mathews;NCHS Data Brief,2016
5. On the comparative frequency of twin-bearing in different pregnancies;Duncan;Edinb Med J,1865