A manual on methods for the assessment of secondary productivity in fresh waters 
edited by John A. Downing and Frank H. Rigler 
 - 2nd ed. 
 - Oxford  Blackwell Scientific Publications  1984. 
 - 501p. ill. 24cm. 
<br/><br/><label>ISBN: </label>0632006161 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Freshwater productivity--Measurement