APA

Williams M. A., Hickok D. E., Zingheim R. W., Luthy D. A., Kimelman J., Nyberg D. A. & Mahony B. S. (19921117). Elevated maternal serum alpha-fetoprotein levels and midtrimester placental abnormalities in relation to subsequent adverse pregnancy outcomes. : American journal of obstetrics and gynecology.

Chicago

Williams M A, Hickok D E, Zingheim R W, Luthy D A, Kimelman J, Nyberg D A and Mahony B S. 19921117. Elevated maternal serum alpha-fetoprotein levels and midtrimester placental abnormalities in relation to subsequent adverse pregnancy outcomes. : American journal of obstetrics and gynecology.

Harvard

Williams M. A., Hickok D. E., Zingheim R. W., Luthy D. A., Kimelman J., Nyberg D. A. and Mahony B. S. (19921117). Elevated maternal serum alpha-fetoprotein levels and midtrimester placental abnormalities in relation to subsequent adverse pregnancy outcomes. : American journal of obstetrics and gynecology.

MLA

Williams M A, Hickok D E, Zingheim R W, Luthy D A, Kimelman J, Nyberg D A and Mahony B S. Elevated maternal serum alpha-fetoprotein levels and midtrimester placental abnormalities in relation to subsequent adverse pregnancy outcomes. : American journal of obstetrics and gynecology. 19921117.