Fenchel, Werner. <br/><br/>
Elementary geometry in hyperbolic space.   
by Werner Fenchel. 
 - Berlin  Walter De Gruyter  1989 
 - xi, 225p. 
 - de Gruyter studies in mathematics 11 .
<br/><br/><label>ISBN: </label>0899254934 
<br/><br/><label>Dewey Class. No.: </label>516.9  / N89