Basic trigonometry :  module VI / 
Leon J. Ablon,...(et al.) 
 - 2nd ed. 
 - Menlo Park :  Cummings,  1976 
 - 124 p. :  ill. ;  24 cm. 
<br/><br/><label>LCCN: </label>75-21084 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Trigonometry