Thomson Scientific, Institute for Scientific Information (ISI) has included Franco Preparata and Roberto Tamassia in the list of the most highly cited computer science authors worldwide, based on citations in venues indexed by ISI for the period 1981-1999. In the website ISIHighlyCited.com, ISI features the "preeminent individual researchers in each of 21 subject categories who have demonstrated great influence in their field as measured by citations to their work--the intellectual debt acknowledged by their colleagues." For the field of computer science, the list contains 319 people. In addition to Brown CS faculty Franco and Roberto, the list includes Brown CS alums Ed Lazowska and John Stankovic. The venues indexed by ISI include the most prestigious scientific journals and selected conference proceedings. Articles published in such venues are the primary source used by the National Research Council in assessing scholarly productivity in science and engineering.