Columbia subject headings:
Greeting cards--Russia--History.
Greeting cards--Russia.
Greeting cards--Soviet Union--History.
Greeting cards--Soviet Union.
Postcards--Russia--History.
Postcards--Russia.
Postcards--Soviet Union--History.
Postcards--Soviet Union.
Harvard subject headings:
Postcards--Russia--Themes, motives.
Postcards--Russia.
Postcards--Soviet Union--Themes, motives.
Postcards--Soviet Union.
Princeton subject headings:
Postcards--Russia.
Postcards--Soviet Union.