http://jme.bmjjournals.com/cgi/content/full/30/6/593 Updated information and services can be found at: These include: References http://jme.bmjjournals.com/cgi/content/full/30/6/593#otherarticles 1 online articles that cite this article can be accessed at: Rapid responses http://jme.bmjjournals.com/cgi/eletter-submit/30/6/593 You can respond to this article at: http://jme.bmjjournals.com/cgi/co...

http://bmj.com/cgi/content/full/330/7481/2 Updated information and services can be found at: These include: References http://bmj.com/cgi/content/full/330/7481/2#BIBL This article cites 13 articles, 6 of which can be accessed free at: Rapid responses http://bmj.com/cgi/eletter-submit/330/7481/2 You can respond to this article at: http://bmj.com/cgi/content/full/330/7481/2#responses free at: 2 r...

http://bmj.com/cgi/content/full/328/7439/536 Updated information and services can be found at: These include: References http://bmj.com/cgi/content/full/328/7439/536#otherarticles 4 online articles that cite this article can be accessed at: Rapid responses http://bmj.com/cgi/eletter-submit/328/7439/536 You can respond to this article at: http://bmj.com/cgi/content/full/328/7439/536#responses fr...

http://bmj.com/cgi/content/full/332/7535/190 Updated information and services can be found at: These include: References http://bmj.com/cgi/content/full/332/7535/190#otherarticles 2 online articles that cite this article can be accessed at: Rapid responses http://bmj.com/cgi/eletter-submit/332/7535/190 You can respond to this article at: http://bmj.com/cgi/content/full/332/7535/190#responses fr...

http://bmj.com/cgi/content/full/334/7583/20 Updated information and services can be found at: These include: References http://bmj.com/cgi/content/full/334/7583/20#BIBL This article cites 8 articles, 1 of which can be accessed free at: Rapid responses http://bmj.com/cgi/eletter-submit/334/7583/20 You can respond to this article at: http://bmj.com/cgi/content/full/334/7583/20#responses for free ...

http://bmj.com/cgi/content/full/336/7637/184 Updated information and services can be found at: These include: References http://bmj.com/cgi/content/full/336/7637/184#BIBL This article cites 12 articles, 4 of which can be accessed free at: Rapid responses http://bmj.com/cgi/eletter-submit/336/7637/184 You can respond to this article at: http://bmj.com/cgi/content/full/336/7637/184#responses free...

http://bmj.com/cgi/content/full/328/7445/950 Updated information and services can be found at: These include: References http://bmj.com/cgi/content/full/328/7445/950#BIBL This article cites 7 articles, 3 of which can be accessed free at: Rapid responses http://bmj.com/cgi/eletter-submit/328/7445/950 You can respond to this article at: http://bmj.com/cgi/content/full/328/7445/950#responses free ...

http://bmj.com/cgi/content/full/328/7446/988 Updated information and services can be found at: These include: Data supplement http://bmj.com/cgi/content/full/bmj.38070.503009.EE/DC1 "Security statement" References http://bmj.com/cgi/content/full/328/7446/988#otherarticles 6 online articles that cite this article can be accessed at: http://bmj.com/cgi/content/full/328/7446/988#BIBL This article ...

http://bmj.com/cgi/content/full/334/7598/842 Updated information and services can be found at: These include: Data supplement http://bmj.com/cgi/content/full/334/7598/842/DC1 "References" References http://bmj.com/cgi/content/full/334/7598/842#otherarticles 6 online articles that cite this article can be accessed at: http://bmj.com/cgi/content/full/334/7598/842#BIBL This article cites 19 articl...

http://bmj.com/cgi/content/full/329/7458/170 Updated information and services can be found at: These include: References http://bmj.com/cgi/content/full/329/7458/170#BIBL This article cites 4 articles, 1 of which can be accessed free at: Rapid responses http://bmj.com/cgi/eletter-submit/329/7458/170 You can respond to this article at: http://bmj.com/cgi/content/full/329/7458/170#responses free ...