. 2013 Oct 8;13:395. doi: 10.1186/1472-6963-13-395
Copyright © 2013 Bardsley 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 1.
Crude monthly rates of contact.