APA (7th ed.) Citation

Wittwer, S. H. (1976). Biological nitrogen fixation. [Michigan State University Agricultural Experiment Station?].

Chicago Style (17th ed.) Citation

Wittwer, S. H. Biological Nitrogen Fixation. [East Lansing?]: [Michigan State University Agricultural Experiment Station?], 1976.

MLA (9th ed.) Citation

Wittwer, S. H. Biological Nitrogen Fixation. [Michigan State University Agricultural Experiment Station?], 1976.

Warning: These citations may not always be 100% accurate.