Authors: S J Schrag; S Zywicki; M M Farley; A L Reingold; L H Harrison; L B Lefkowitz; J L Hadler; R Danila; P R Cieslak; A Schuchat Journal: N Engl J Med Date: 2000-01-06 Impact factor: 91.245
Authors: R Matorras; A García-Perea; F Omeñaca; M Diez-Enciso; R Madero; J A Usandizaga Journal: Eur J Obstet Gynecol Reprod Biol Date: 1991-06-05 Impact factor: 2.435