We want to encourage the circulation of this work. We therefore have an open access policy which enables anyone to download, save, perform or distribute this work in any format, including translation, without written permission, subject to the terms of the creative commons license. Its conditions are:
· The work is not altered and is used in full
· The work is not sold or resold
· This summary is displayed
· A copy of the work or link to its use online is sent to firstname.lastname@example.org
You are also welcome to ask for permission to use this work for purposes other than those covered by the license.
We gratefully acknowledge the work of Creative Commons in inspiring our approach to copyright. To find out more go to www.creativecommons.org