Submitted on: 17 October 1998.
Revised on: 28 January 1999.
Accepted on: 03 March 1999.
___________________Gaceta Sanitaria---ELSEVIER
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http://reply.papertrans.cn/2/104/10351/10351-23.png
Submitted on: 05 March 2004.
Revised on: 10 June 2004.
Accepted on: 07 August 2004.
___________________Gaceta Sanitaria---ELSEVIER
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Submitted on: 14 July 2002.
Revised on: 04 August 2002.
Accepted on: 25 August 2002.
___________________Gaceta Sanitaria---ELSEVIER
http://reply.papertrans.cn/2/104/10351/10351-27.png
Submitted on: 18 May 2014.
Revised on: 20 August 2014.
Accepted on: 10 September 2014.
___________________Gaceta Sanitaria---ELSEVIER
http://reply.papertrans.cn/2/104/10351/10351-29.png
Submitted on: 13 January 2025.
Revised on: 13 February 2025.
Accepted on: 10 March 2025.
___________________Gaceta Sanitaria---ELSEVIER