http://pps97.cryst.bbk.ac.uk/course/section2/index.html
If you have any problems please don't hesitate to contact us.
Cheers,
Dave H.
Dave Houldershaw
PPS'97 Technical Coordinator
Dept. Crystallography, Birkbeck Coll. London
tel:- 0171 631 6853 fax:- 0171 631 6803