Reader Comments

Post a new comment on this article

Referee comments: Referee 1

Posted by PLOS_ONE_Group on 07 Mar 2008 at 17:53 GMT

Referee 1's review:

The authors have addressed the comments raised in the reviews very well. I have no further comments.

**********
N.B. These are the comments made by the referee when reviewing an earlier version of this paper. Prior to publication the manuscript has been revised in light of these comments and to address other editorial requirements.