. 2009 Apr 3;10(1):26. doi: 10.1186/1465-9921-10-26
Copyright ©2009 Xu 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.