. 2013 May 14;54(4):819–824. doi: 10.3349/ymj.2013.54.4.819
© Copyright: Yonsei University College of Medicine 2013
This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0/) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.