Columbia subject headings:
Mollusks--Illinois.
Vermilion River (Ill. and Ind.)
Harvard subject headings:
Big Vermilion river.
Mollusks--Effect of water pollution on--Illinois.
Mollusks--Illinois.
Mollusks--Vermilion River (Ill. and Ind.)
Water--Pollution--Environmental aspects--Vermilion River (Ill. and Ind.)
Princeton subject headings: