Intermediate trigonometry 
By B.C. Das 
 - 44th ed. 
 - Calcutta:  U.N. Dhur & sons private limited,  1999. 
 - xvi,296p. 
<br/><br/><label>ISBN: </label>81-85624-85-2 
<br/><br/><label>Subjects--Index Terms: </label>Geometry Trigonometry 
<br/><br/><label>Dewey Class. No.: </label>516.24