. 2004 Aug 5;2:6. doi: 10.1186/1478-4505-2-6
Copyright © 2004 Gonzalez-Block; 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 1.
Concepts and indicators