000			00366nam a2200145Ia 4500
008			160615s9999 xx 000 0 und d
100			_aGARDNER(Martin)
245			_aPenrose tiles to trapdoor ciphers ...and the return of Dr. Matrix
260			_bFreeman
260			_c1989
300			_aix p. + 311
942			_cBooks
999			_c19008 _d19008