Ricklefs, R E <br/><br/>
Structure in ecology: a hierarchical concept of ecosystems.  [electronic resource] 

 -  Science (New York, N.Y.)  Apr 1987 
 - 206-7 p.  digital 
<br/><br/> Publication Type: Journal Article 
<br/><br/><label>ISSN: </label>0036-8075 
<br/><br/><label>Standard No.: </label>10.1126/science.236.4798.206-a  doi