Cooray, PG. <br/><br/>
Commonsense about our environment 

 -  National resources energy and science authority  1987 
 - 89p., ill.,  22 cm 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Ecology <br/>Landslides <br/>Water supplies <br/>Pollution
<br/><br/><label>Universal Decimal Class. No.: </label>581.52  / COO