Durnwald CP, Mele L, Spong CY, Ramin SM, Varner MW, Rouse DJ, Sciscione A, Catalano P, Saade G, Sorokin Y, Tolosa JE, Casey B, Anderson GD; Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD) Maternal-Fetal Medicine Units Network (MFMU).
Obstet Gynecol. 2011 Apr;117(4):819-27.