Koster, Raph. <br/><br/>
A theory of fun for game design / 
by Raph Koster. 
 - Scottsdale, AZ :  Paraglyph Press,  2005. 
 - x, 244 p. :  ill. ;  18 x 24 cm. 
<br/><br/><label>ISBN: </label>1932111972 9781932111972