I think he probably spoke about "Designing and Programming Personal Expert Systems" by Carl Townsend that dates back to 1986. From http://www.faqs.org/faqs/com

I think he probably spoke about "Designing and Programming Personal Expert Systems" by Carl Townsend that dates back to 1986. From http://www.faqs.org/faqs/computer-lang/forth-faq/part5/ http://www.faqs.org/faqs/computer-lang/forth-faq/part5/ Contains LISP and Prolog emulations in Forth, including a unification algorithm. It also has some minimum distance classifier code. The application is fault diagnosis in locomotives.