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. 2016 Nov 18;16:663. doi: 10.1186/s12913-016-1904-6

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© The Author(s). 2016

Open AccessThis article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. 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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Fig. 1 — PRISMA Diagram. *168 papers reporting data on any type of fidelity from the forward citation search (left hand side flow) can be calculated by the sum of 52+83+33. Search strategies were conducted consecutively; duplicates removed from the electronic database search results therefore included papers that had already been identified in the forward citation search