Symbols of American libraries. 

 - Washington  Library of Congress. 
 - [1st]- 1932- 
<br/><br/>Vols. for 1932-69 issued by the Union Catalog Division, Library of Congress; 1976- by its Catalog Publication Division. 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Libraries--Abbreviations.--United States