On 22 November 2015 at 13:36, Peter Blight <peter at blight.demon.co.uk> wrote: > There may be things here you have missed out on: > <http://cccbr.org.uk/pubs/online/leary.pdf> I've had a quick peek and that looks like what I need - thanks. I'll go through it in detail - thanks! -- Alan Burlison --