Acknowledgements

This unit was written by

Except for third party materials and otherwise stated in the acknowledgements section, this content is made available under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 Licence [Tip: hold Ctrl and click a link to open it in a new tab. (Hide tip)] .

The material acknowledged below is Proprietary and used under licence (not subject to Creative Commons Licence). Grateful acknowledgement is made to the following sources for permission to reproduce material in this unit:

Unit image Acknowledgements provided in production specification or by LTS-Rights

Please include further acknowledgements as provided in production specification or by LTS-Rights in following order: Text Images Figures Illustrations Tables AV Interactive assets

Every effort has been made to contact copyright owners. If any have been inadvertently overlooked, the publishers will be pleased to make the necessary arrangements at the first opportunity.

Don't miss out:

1. Join over 200,000 students, currently studying with The Open University – http://www.open.ac.uk/ choose/ ou/ open-content

2. Enjoyed this? Find out more about this topic or browse all our free course materials on OpenLearn – http://www.open.edu/ openlearn/

3. Outside the UK? We have students in over a hundred countries studying online qualifications – http://www.openuniversity.edu/ – including an MBA at our triple accredited Business School.