Johnson, James <br/><br/>
The classification of certain virus diseases of the potato / 
by James Johnson 
 - Madison, Wisc. :   Agricultural experiment station of the University of Wisconsin 
 - 24 p. 
<br/><br/><label>LCCN: </label>199014 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Papa -- enfermedades por virus