Heim, Mary Ellen <br/><br/>
Open twenty-four hours :  a case study / 
Mary Ellen Heim. 
 - Illinois :  University of Illinois Graduate School of Library and Information Science,  1990 
 - 47p.;  23cm. 
 - Occasional papers ;   no.187 .
<br/><br/><label>ISSN: </label>0276176 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Library service agencies.
<br/><br/><label>Dewey Class. No.: </label>025