Geer, Helen Thornton,  1903- <br/><br/>
Charging systems. / 
Helen Thornton Geer 
 - Chicago:  American Library Association,  c1955 [Printing 1963] 
 - 177 p. :  illus. ;  22 cm. 
<br/><br/>Include bibliography 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Charging systems (Libraries)
<br/><br/><label>Dewey Class. No.: </label>025.6  / GEC 1963