Ballmann, Werner <br/><br/>
Lectures on spaces of nonpositive curvature   

 - Basel  Birkhauser Verlag  1995 
 - v, 112p. Bibl. Index. 
 - DMV Seminar band    25 .
<br/><br/> With an appendix by Misha Brin Ergodicity of Geodesic Flows   
<br/><br/><label>ISBN: </label>0817652426 
<br/><br/><label>Dewey Class. No.: </label>516  / B192.LS