. 2009 Aug 17;11(4):R124. doi: 10.1186/ar2790
Copyright © 2009 van der Heijde 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.