Buchin, Su. <br/><br/>
Lectures on Differential Geometry /  
translated by K.C. Chang. 
 - 1st ed /  
 - Singapore 9128 :   World Scientific Publishing Co pte Ltd.. 
 - p.149 :  
<br/><br/><label>ISBN: </label>9971-83-003-5 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Mathematics
<br/><br/><label>Dewey Class. No.: </label>B6:3  / M1;1