. 2016 Oct 11;66(653):e861–e870. doi: 10.3399/bjgp16X687577
© British Journal of General Practice 2016
This is an OpenAccess article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted reuse, distribution, and reproduction in any medium, provided the original work is properly cited.