McCulloch, W.S. and Walter Pitts. "The Statistical Organization of Nervous Activity", as it appeared in the June 1948 monthly issue of Biometrics (the Biometrics Section, American Statistical Association), volume 4, No. 2. Offered is the monthly issue in the original wrappers, containing pp 91-150, of which the McCulloch/Pitts occupies pp 91-99. Fine condition, with two ownership stamps. $350
See our other papers by McCulloch and Pitts (along with a description of their work) here.