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. 2014 Jan 29;12:15. doi: 10.1186/1741-7015-12-15

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Copyright © 2014 Catalá-López 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/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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Global collaborative network between countries. Note: Node sizes are proportional to the number of papers and line thicknesses are proportional to the number of collaborations.