W. McCulloch, W. Pitts, A Logical Calculus of Ideas Immanent in Nervous Activity, Bulletin of Mathematical Biophysics, 1943, pp. 5:115–133..Ripubblicato in: "A Logical Calculus of the Ideas Immanent in Nervous Activity". With Walter Pitts. In: Bulletin of Mathematical Biophysics Vol 5, pp 115–133.