http://dx.doi.org/10.1136/bjsm.2007.035568 | | | | DOI Link |
http://bjsm.bmj.com/content/41/9/582.full | 10/20/2014 | | Item is within a limited-access website | |
http://bjsm.bmj.com/content/41/9/582.full.pdf | 10/20/2014 | PDF Reader | Item is within a limited-access website | |