Britannica Global Edition 
Dale H. Hoiberg and Michael Leavy 
 - Chicago  Encyclopedia Britannica,Inc.  2011 
 - 610p.:ill, 
<br/><br/><label>ISBN: </label>978-1-62513-418-9 
<br/><br/><label>Dewey Class. No.: </label>032  / H719 V.1