Martin Gardner's article on aperiodic tiling:

Scientific American 236 (1977) 111-119

Roger Penrose's Pentaplexity article on aperiodic tiling:

Eureka 39(1978) 16-22

Steven Dworkin's article on the spectrum of aperiodic structures:

J. Math. Phys. 34(1993) 2965-2967

Aperiodicity subject to noise, or quasicrystals at positive temperature:

Hans Koch and Charles Radin: J. Stat. Phys. 138(2010) 465-475

David Aristoff and Charles Radin: J. Phys. A: Math. Theor. 44(2011), 255001.

Encyclopedia of Tiling:

Some web pages