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. 2014 Sep 10;14:319. doi: 10.1186/1471-2393-14-319

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© Berger et al.; licensee BioMed Central Ltd. 2014

This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), 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.

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Summary of the literature search and review process (number of articles). *Total may exceed the number in the corresponding box because articles could be excluded for more than one reason at this level. CINAHL (Cumulative Index to Allied Health and Nursing Literature).