Benson, Robert E. <br/><br/>
Natural trignometric functions containing the natural sine, cosine, tangent and cotangent to seven decimal places for every ten seconds of arc from 0 to 90 centigrades semi-quadrantly arranged /    
Robert E. Be nson. 
 - Illinois :   Charles T. Powner Co.,   c1974. 
 - 181 p. :    ill. ;    24 cm. 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Trigonometric sums.--------
<br/><br/><label>Dewey Class. No.: </label>516.240212 BEN