Plane and spherical trigonometry 
Lumabas, Rogelio S. 
 -  Phoenix Publishing House, Inc.  1980 
 - xii, 396 pages. 
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<br/><br/><label>ISBN: </label>9-71060586-0 
<br/><br/><label>Dewey Class. No.: </label>F 514 L97p 1980