Downs, J.W. <br/><br/>
Practical conic sections :  The geometric properties ellipses, parabolas and hyperbolas / 
by J.W. Downs. 
 - Mineola, N.Y. :  Dover,  2003. 
 - XII, 100 p. :  fig. ;  23 cm. 
<br/><br/><label>ISBN: </label>0-486-42876-1 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Conic sections