Change Log
Major update published on 4 March 2013
One of the key features of Living Reviews is that its articles are kept up-to-date by their authors. A major update is considered a new publication. As such it is again subject to peer review and is issued with a new publication number.
Global description:
Substantial revision of most sections. Addition of Jonathan Downing as co-author. Number of references increased from 247 to 495.
Previous version:
http://www.livingreviews.org/lrr-2006-2