Peck, Lyman C.,  1920- <br/><br/>
Secret codes, remainder arithmetic, and matrices / 
Lyman C. Peck. 
 - Reston, Virginia :  National Council of Teachers of Mathematics,  1961. 
 - 54 p. :  ill. 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Arithmetic.<br/>Ciphers.<br/>Matrices.