Copyright © 2010 Open Object Press. All rights reserved. You may take electronic copy of this work and distribute it if you don't change the content. You can also print a copy to be read by yourself only. We have contracts with different publishers in different countries to sell and distribute paper or electronic based versions of this work (translated or not) in bookstores. This helps to distribute and promote the Open ERP product. It also helps us to create incentives to pay contributors and authors with the royalties. Due to this, grants to translate, modify or sell this work are strictly forbidden, unless OpenERP s.a. (representing Open Object Press) gives you a written authorisation for this. While every precaution has been taken in the preparation of this work, the publisher and the authors assume no responsibility for errors or omissions, or for damages resulting from the use of the information contained herein. Published by Open Object Press, Grand Rosiere, Belgium