Hopfen, Hans Joachim. <br/><br/>
Farm implements for arid and tropical regions / 
prepared by H. J. Hopfen. 
 - 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/><label>Subjects--Topical Terms: </label><br/>Agricultural implements.