APA
Gardner M., . (1997). Penrose tiles to trapdoor ciphers : --and the return of Dr. Matrix. Wsshington, DC: Mathematical Association of America.
Chicago
Gardner Martin, . 1997. Penrose tiles to trapdoor ciphers : --and the return of Dr. Matrix. Wsshington, DC: Mathematical Association of America.
Harvard
Gardner M., . (1997). Penrose tiles to trapdoor ciphers : --and the return of Dr. Matrix. Wsshington, DC: Mathematical Association of America.
MLA
Gardner Martin, . Penrose tiles to trapdoor ciphers : --and the return of Dr. Matrix. Wsshington, DC: Mathematical Association of America. 1997.