HOPFIELD, J. J. Neural networks and physical systems with emergent collective computational abilities. Proc. Nat. Acad. Sci. USA. 1982, 79, 2554-2558
HOPFIELD, J. J. Neurons with graded response have collective computational properties like those of two-state neurons. Proc. Nat. Acad. Sci. USA. 1984, 81, 3088-3092