Heldt, P.M. <br/><br/>
Motor vehícles and tractors 
P.M. Heldt 
 - 678 p.  il (figuras fotos)  22 cms. 
<br/><br/><label>Subjects--Topical Terms: </label><br/>ciencias aplicadas
<br/><br/><label>Dewey Class. No.: </label>600  / HEL MOT 1929