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. 2007 Jan 26;2(1):e5. doi: 10.1371/journal.pctr.0020005

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© 2007 Smith et al.

This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are properly credited.

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Red vertical line in center of each figure depicts the demarcation between Step II and Step III. Fractions in upper right corner of each figure portray the number of participants who were eligible to enter Step III in each group.