Desing . elements of reusable object-oriented sofware / 
Erich Gamma ... [et.al.]. 
 - 1a ed. 
 - Canada :  Addison - Wealey,  2013 
<br/><br/><label>ISBN: </label>0-201-63361-2 
<br/><br/><label>Dewey Class. No.: </label>005.12 D28