Ymas, Sergio E. <br/><br/>
Plane trigonometry / 
Sergio E. Ymas. 
 - Rev. ed. 
 - Manila :  The Author,  1996. 
 - 231 p. : ill. 
<br/><br/> Includes appendices and bibliography. 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Trigonometry.