Field work in ecology for secondary schools in tropical countries ; edited by P.J. Kelly. 

 - [S.l.]:   Unesco,   [19--].  
 - 273 p. :  ill. ;  28 cm. 
 -  30 .
<br/><br/><label>Subjects--Topical Terms: </label><br/>Ecology--Study and teaching
<br/><br/><label>Dewey Class. No.: </label>333.7071