| Date | Event | Description |
|---|---|---|
| 7 July 2010 | New citation required and major changes | Protocol substantially updated and reinstated. |
| 11 November 2009 | Amended | Protocol withdrawn from publication as it was out of date. Author contact details edited. |
| 29 January 2009 | Amended | Author contact details edited. |
| 24 September 2008 | Amended | Converted to new review format. |
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