Hopfen, Hans Joachim. <br/><br/>
Farm implements for arid tropical regions /    
prepared by H. J. Hop fen. 
 - Rev. ed. 
 - Rome :   Food and Agriculture Organization of the United Nations ,   1969. 
 - xii, 159 p. :    ill. ;    23 cm. 
 - FAO Agricultural development paper ;   no.91. .
<br/><br/>Includes bibliographical references : p.147-150. 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Agricultural implements.--------