Copies of the pages (or extracts of text from those pages) may be taken for personal use. However, where multiple copies of pages (or extracts) are to be made, a formal request should be made to the author at D.J.Jukes@reading.ac.uk. No reasonable request will be refused (particularly where it is for educational purposes) but a small charge will be requested where the use is for commercial activity.

All such material should be marked with the statement:

‘This material is derived from the web pages of Dr David Jukes, The University of Reading, UK, and is used with the author’s permission.’

Thank you for your co-operation in this matter.