. 2007 Feb 13;7:19. doi: 10.1186/1471-2148-7-19
Copyright © 2007 Wolf et al; licensee BioMed Central Ltd.
This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Figure 2.
