. 2014 Mar 17;9(1):16. doi: 10.1186/2049-6958-9-16
Copyright © 2014 Magnoni 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/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly credited. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.
Figure 4.
Causes for COPD patients to submit to subsequent examinations.