Weizenbaum, Joseph. "ELIZA — A Computer Program for the Study of Natural Language Communication Between Man and Machine." Communications of the ACM, vol. 9, no. 1, January 1966, pp. 36–45.
Weizenbaum, Joseph. Computer Power and Human Reason: From Judgment to Calculation. W. H. Freeman, 1976.
Source Code
elizagen.org — Jeff Shrager's ELIZA archaeology project, including the original MAD-SLIP source code transcription from Weizenbaum's MIT archives.
anthay/ELIZA — Anthony Hay's annotated transcription and faithful C++ reimplementation.