Cite
MLA Citation
Xu Xiong et al.. “Maternal Age and Preterm Births in Singleton and Twin Pregnancies Conceived By In Vitro Fertilisation in the United States.” Paediatric and perinatal epidemiology, vol. 29, no. 1, 2015, pp. 22–30. http://access.bl.uk/ark:/81055/vdc_100025008963.0x00000d