Sir Arthur Keith (1927). “Concerning man's origin: being the presidential address given at the meeting of the British association held in Leeds on August 31, 1927, and recent essays on Darwinian subjects”
"The Emotion Machine: Commonsense Thinking, Artificial Intelligence, and the Future of the Human Mind". Book by Marvin Minsky, p. 239, November 13, 2007.
Boris Yeltsin's speech to the summit of the Organization for Security and Co-operation in Europe (OSCE) in Istanbul, news.bbc.co.uk. November 18, 1999.