The azolla-anabaena complex and its uses in rice culture / 
I. Watanabe ... [et al.] 
 - Manila :  International Rice Research Institute,  1981 
 - 11 p. 
 - IRRI research paper series ;  no. 69 .
<br/><br/> Cover title. 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Azolla as fertilizer.<br/>Rice--Fertilizers.