. 2014 Mar 19;14:18. doi: 10.1186/1472-6947-14-18
Copyright © 2014 Groothuis-Oudshoorn 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 credited.
Figure 1.
Choice set example.