Ocana, Hernaldo P., <br/><br/>
Manipulative Teaching Devices : A Support Material in Trigonometry / 
Hernaldo P. Ocana 
 - San Miguel, Iriga City  USANT  2019 
 - 218 leaves : 
<br/><br/>Includes bibliographical references 
<br/><br/><label>Dewey Class. No.: </label>512  / O1