"About Art, Chess, Beauty and Depth, Creativity, Telepathy and Artificial Intelligence". Interview with Ugo Dossi, en.chessbase.com. December 21, 2005.
"The Metropolis and Modern Life" by Georg Simmel (1903), translated by Kurt Wolff in "The Sociology of Georg Simmel" edited by D. Weinstein, New York: Free Press, (p. 422), 1950.