CHINESE JOURNAL OF OBSTEICS AND GYNECOLOGY, Volume 34, Issue 8,1999, Pages 494, doi:10.3760/j.issn:0529-567X.1999.08.017
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CHINESE JOURNAL OF OBSTEICS AND GYNECOLOGY, Volume 34, Issue 8,1999, Pages 453, doi:10.3760/j.issn:0529-567X.1999.08.001
CHINESE JOURNAL OF OBSTEICS AND GYNECOLOGY, Volume 34, Issue 8,1999, Pages 467, doi:10.3760/j.issn:0529-567X.1999.08.006
CHINESE JOURNAL OF OBSTEICS AND GYNECOLOGY, Volume 34, Issue 8,1999, Pages 509, doi:10.3760/j.issn:0529-567X.1999.08.028