Submitted on: 16 September 2010.
Revised on: 10 October 2010.
Accepted on: 27 October 2010.
OBSTETRICAL & GYNECOLOGICAL SURVEY
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Submitted on: 03 March 2005.
Revised on: 16 March 2005.
Accepted on: 10 April 2005.
OBSTETRICAL & GYNECOLOGICAL SURVEY
http://reply.papertrans.cn/3/236/23504/23504-34.png
http://reply.papertrans.cn/3/236/23504/23504-35.png
Submitted on: 17 December 2011.
Revised on: 27 January 2012.
Accepted on: 22 February 2012.
OBSTETRICAL & GYNECOLOGICAL SURVEY