Submitted on: 24 April 2020.
Revised on: 12 June 2020.
Accepted on: 17 July 2020.
___________________BMJ Evidence-Based Medicine---BMJ PUBLISHING GROUP
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Submitted on: 05 April 2014.
Revised on: 18 May 2014.
Accepted on: 06 June 2014.
___________________BMJ Evidence-Based Medicine---BMJ PUBLISHING GROUP
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Submitted on: 18 August 2000.
Revised on: 10 September 2000.
Accepted on: 17 October 2000.
___________________BMJ Evidence-Based Medicine---BMJ PUBLISHING GROUP
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Submitted on: 09 June 1999.
Revised on: 03 September 1999.
Accepted on: 16 September 1999.
___________________BMJ Evidence-Based Medicine---BMJ PUBLISHING GROUP
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Submitted on: 24 January 1998.
Revised on: 19 March 1998.
Accepted on: 14 April 1998.
___________________BMJ Evidence-Based Medicine---BMJ PUBLISHING GROUP