Umponstira, C., 		Kawayaskul, S., 		Chuchaung, S., & 		Homhaul, W.
(2013).
 Effect of Ozone on Nitrogen Fixation, Nitrogenase Activity and Rhizobium of Cowpea (Vigna unguiculata (L.) Walp).
<em>Naresuan University Journal: Science And Technology (NUJST), 17</em>(3), 213-220.
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