Encyclopaedia Britannica <br/><br/>
Energy and movement 

 - Chicago  Encyclopaedia Britannica lnc.  2009 
 - 101 
<br/><br/><label>ISBN: </label>978-1-59339-855-2 
<br/><br/><label>Subjects--Facted Index Terms: </label><br/>Energy and movement<br/>
<br/><br/><label>Dewey Class. No.: </label>R503