There is a PDF that contains some of the work from this group Check ftp://ftp.academ.com/pub/misc/troublet.pdf for this document. -- Stan | PGP Key ID: 55CB6421 | Opinions expressed are only mine. Olan | Phone: +1-713-793-0222 | Email: sob@academ.com Barber | Fax: +1-713-793-0221 | http://www.academ.com/~sob