Kells, Lyman M. <br/><br/>
Plane and spherical trigonometry / 
Lyman M. Kells, Wills F. Kern and James R. Bland. 
 - 3rd ed. - 
 - New York:  McGraw-Hill,  c1978. 
 - x, 118 p. :  ill. ;  22 cm. 
<br/><br/>Includes appendices and index. 
<br/><br/><label>ISBN: </label>97108-1917-8 (pbk.) 
<br/><br/><label>Subjects--Geographic Terms: </label>