Columbia subject headings:
Ammonia--Environmental aspects.
Ammonia--Physiological effect.
Ammonia--Toxicology.
Harvard subject headings:
Ammonia--Environmental aspects.
Ammonia--Physiological effect.
Ammonia--Toxicology.
Princeton subject headings:
Ammonia--Environmental aspects.
Ammonia--Physiological effect.
Ammonia--Toxicology.