Geer Helen Thorton. <br/><br/>
Charging systems 
Geer Helen Thorton. 
 -  1955 
<br/><br/><label>Standard No.: </label>5,264 
<br/><br/><label>Source: </label> Textual 
<br/><br/><label>Subjects--Topical Terms: </label><br/>LIBRARY SCIENCE
<br/><br/><label>Dewey Class. No.: </label>2:6, J5