Croft, Hallard T. <br/><br/>
Unsolved problems in geometry   
Hallard T.Croft, Kenneth J. Falconer, Richard K. Guy 
 - New York  Springer-Verlag  1991 
 - xv, 198p. 
 - Problem book in mathematics Unsolved problems in intuitive mathematics  V.2 .
<br/><br/><label>ISBN: </label>0387975063 
<br/><br/><label>Dewey Class. No.: </label>516  / N911