Columbia subject headings:
Air--Pollution--Toxicology.
Carbon monoxide--Environmental aspects.
Carbon monoxide--Toxicology.
Harvard subject headings:
Air--Pollution--Toxicology.
Carbon monoxide--Environmental aspects.
Carbon monoxide--Toxicology
Princeton subject headings:
Air--Pollution--Toxicology.
Carbon monoxide--Environmental aspects.
Carbon monoxide--Toxicology.