Columbia subject headings:
Enzymes--Congresses.
Molybdenum--Metabolism--Congresses.
Molybdenum--Physiological effect--Congresses.
Nitrogen-fixing microorganisms--Congresses.
Harvard subject headings:
Enzymes--Congresses.
Molybdenum--Metabolism--Congresses.
Molybdenum--Physiological effect--Congresses.
Nitrogen-fixing microorganisms--Congresses.
Princeton subject headings:
Enzymes--Congresses.
Molybdenum--Metabolism--Congresses.
Molybdenum--Physiological effect--Congresses.
Nitrogen-fixing microorganisms--Congresses.