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008			970211s1997 dcua b 001 0 eng
020			_a0883855216 (pbk.)
080			_a51-8 _bGAR
100	1		_aGardner, Martin, _92202
245	1	0	_aPenrose tiles to trapdoor ciphers : _b--and the return of Dr. Matrix / _cMartin Gardner.
250			_aRev. ed.
260			_aWashington, D.C. : _bMathematical Association of America, _cc1997.
300			_aix, 319 p. : _bill. (some col.) ;
653			_aMathematical recreations
942			_cBK
999			_c161807 _d161807