Gardner (1985) MNS; Stillings et. al. (1989) (Chapters 4 and 5); Luger (1994) (See sec. )
http://www.acm.org/crossroads/
http://www.generation5.org/
For computability and Turing Machine see:
Penrose, Roger (1989) The Emperor's New Mind: Concerning Computers, Minds and the Laws of Physics. Oxford: OUP.