Submitted on: 02 December 2002.
Revised on: 20 March 2003.
Accepted on: 25 April 2003.
___________________AMERICAN JOURNAL OF PREVENTIVE MEDICINE
Submitted on: 05 December 2001.
Revised on: 20 March 2002.
Accepted on: 10 May 2002.
___________________AMERICAN JOURNAL OF PREVENTIVE MEDICINE
http://reply.papertrans.cn/1/15/1418/1418-23.png
http://reply.papertrans.cn/1/15/1418/1418-24.png
http://reply.papertrans.cn/1/15/1418/1418-25.png
http://reply.papertrans.cn/1/15/1418/1418-26.png
http://reply.papertrans.cn/1/15/1418/1418-27.png
Submitted on: 17 October 2008.
Revised on: 07 January 2009.
Accepted on: 08 February 2009.
___________________AMERICAN JOURNAL OF PREVENTIVE MEDICINE
Submitted on: 18 March 1998.
Revised on: 17 April 1998.
Accepted on: 12 May 1998.
___________________AMERICAN JOURNAL OF PREVENTIVE MEDICINE
http://reply.papertrans.cn/1/15/1418/1418-30.png