. 2011 Jul 6;2011:948789. doi: 10.1155/2011/948789
Copyright © 2011 Andrew Rosenblum et al.
This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Figure 1.
Distribution of travel distance (n = 23,141).