The study was published online May 17, 2010, in the International Journal of Epidemiology.

Published online February 7, 2006.

Published online March 30, 2011.

Published online April 2, 2008.

Published online June 2, 2008.

Published online May 25, 2002.

Published online April 17, 2013.

Published online April 12, 2005.

Published online May 26, 2011.

The Lancet, published online May 18, 2011.