http://www.google.com/search?q=%223-6+times%22+%22vitamin+d%...
My battery is about to die in the iPhone, so I don't have time to curate the list, but from a quick glance a couple of the sources from the google search look credible.
http://www.google.com/search?q=%223-6+times%22+%22vitamin+d%...
My battery is about to die in the iPhone, so I don't have time to curate the list, but from a quick glance a couple of the sources from the google search look credible.