Columbia subject headings:
Geology, Stratigraphic--Abstracts.
Geology, Stratigraphic--Bibliography.
Geology--Soviet Union--Abstracts.
Geology--Soviet Union--Bibliography.
Harvard subject headings:
Geology, Stratigraphic--Abstracts.
Geology, Stratigraphic--Bibliography.
Geology--Soviet Union--Abstracts.
Geology--Soviet Union--Bibliography.
Princeton subject headings: