Columbia subject headings:
Black Sea--Environmental conditions--Maps--Databases.
Black Sea--Maps--Databases.
Databases.
Marine ecology--Black Sea--Maps--Databases.
Harvard subject headings:
Black Sea--Environmental conditions--Maps--Databases.
Black Sea--Maps--Databases.
Marine ecology--Black Sea--Maps--Databases.
Princeton subject headings:
Black Sea--Environmental conditions--Maps--Databases.
Black Sea--Maps--Databases.
Databases.
Maps.
Marine ecology--Black Sea--Maps--Databases.