. 2011 Feb 4;28(1):Doc16. doi: 10.3205/zma000728
Copyright © 2011 Kruschinski et al.
This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by-nc-nd/3.0/deed.en). You are free to copy, distribute and transmit the work, provided the original author and source are credited.