9[12]Offenbacher S,Katz V,Fertik G,et al.Periodontal infection as a possible risk factor for preterm low birth weight.J Periodontol,1996,67(10 Suppl):1103-1113.
10[13]Jeffcoat MK,Geurs NC,Reddy MS,et al.Periodontal infection and preterm birth:results of a prospective study.J AM Dent Assoc,2001,132:875-880.
