Directory of environmental information sources 
edited by Thomas F.P. Sullivan ; compiled by editorial staff, Government Institutes, Inc. 
 - 5th ed. 
 - Rockville, Md.  Government Institutes  c1995. 
 - xxxi, 299 p.  28 cm. 
<br/><br/> Includes index. 
<br/><br/><label>ISBN: </label>0865874751 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Environmental sciences--Information services--Directories.--United States<br/>Environmental sciences--Bibliography.--United States