Grateful acknowledgement is made to the following sources for permission to reproduce material in this course:
Except for third party materials and otherwise stated (see Creative Commons Attribution-NonCommercial-ShareAlike 4.0 Licence), this content is made available under a
These extracts are taken from DD208 © 2008 The Open University.
Adaptation of work by Michael Bina: Made available under Creative Commons Licence [Details correct as of 1st May 2009]
Don't miss out:
If reading this text has inspired you to learn more, you may be interested in joining the millions of people who discover our free learning resources and qualifications by visiting The Open University - www.open.edu/ openlearn/ free-courses