Churchill, Ruel V <br/><br/>
Operational mathematics / 
by Ruel V Churchill 
 - 2nd ed. 
 - New York :  McGrawhill,  1958. 
 - 337p. : 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Mathematical
<br/><br/><label>Dewey Class. No.: </label>517  / CHU