Butler, William S. <br/><br/>
Secret messages :  concealment, codes, and other types of ingenious communication / 
William S. Butler and L. Douglas Keeney. 
 - New York :  Simon & Schuster,  c2001. 
 - 192 p. :  ill. ;  22 cm. 
<br/><br/>Includes bibliographical references (p. 179-181) and index. 
<br/><br/><label>ISBN: </label>0684869985 
<br/><br/><label>LCCN: </label>00-046368 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Ciphers.<br/>Cryptography.
<br/><br/><label>LC Class. No.: </label>Z103  / .B88 2001 
<br/><br/><label>Dewey Class. No.: </label>652/.8