Brandt, John C.. <br/><br/>
The Physics and Astronomy of the Sun and Stars /  

 - 1st ed /  
 - New York :   McGraw-Hill Book Company. 
 - p.161 :  
<br/><br/><label>Subjects--Topical Terms: </label><br/>Mathematics 
<br/><br/><label>Dewey Class. No.: </label>B920k6  / K6