Nelson, Alfred L; Folley, Karl W <br/><br/>
Plane trigonometry 

 -  Harper & Brothers Publishers, New York  1930 
 - 134 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Trigonometry; Mathematics
<br/><br/><label>Dewey Class. No.: </label>516.24  NEL-P