. 2016 Jul 25;69(5):487–491. doi: 10.4097/kjae.2016.69.5.487
Copyright © the Korean Society of Anesthesiologists, 2016
This is an open-access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/4.0/), which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.