Submitted on: 13 January 2013.
Revised on: 17 February 2013.
Accepted on: 09 April 2013.
___________________Health Services Research and Managerial Epidemiology
http://reply.papertrans.cn/2/112/11151/11151-32.png
http://reply.papertrans.cn/2/112/11151/11151-33.png
Submitted on: 04 August 1999.
Revised on: 30 September 1999.
Accepted on: 11 November 1999.
___________________Health Services Research and Managerial Epidemiology
http://reply.papertrans.cn/2/112/11151/11151-35.png
Submitted on: 31 October 2018.
Revised on: 13 January 2019.
Accepted on: 11 March 2019.
___________________Health Services Research and Managerial Epidemiology