Iversen, Birger. <br/><br/>
Hyberbolic geometry / 
Birger Iversen. 
 - Cambridge :  Cambridge University Press,  1992. 
 - xiv, 298 p. 
 - London Mathematical Society student texts ;  25. .
<br/><br/><label>ISBN: </label>0521435080 (cased) :  �29.95 : Formerly CIP 0521435285 (pbk) 
<br/><br/><label>Nat. Bib. No.: </label>GB93-44645 
<br/><br/><label>Subjects--Index Terms: </label>Plane geometry