Columbia subject headings:
Baltic States--Relations--Germany.
Baltic States--Relations--Switzerland.
Ecology--Study and teaching--Baltic States--History.
Ecology--Study and teaching--Germany--History.
Ecology--Study and teaching--Switzerland--History.
Germany--Relations--Baltic States.
Germany--Relations--Switzerland.
Switzerland--Relations--Baltic States.
Switzerland--Relations--Germany.
Harvard subject headings:
Baltic States--Relations--Germany.
Baltic States--Relations--Switzerland.
Ecology--Study and teaching--Baltic States--History.
Ecology--Study and teaching--Germany--History.
Ecology--Study and teaching--Switzerland--History.
Germany--Relations--Baltic States.
Germany--Relations--Switzerland.
Switzerland--Relations--Baltic States.
Switzerland--Relations--Germany.
Princeton subject headings:
Baltic States--Relations--Germany.
Baltic States--Relations--Switzerland.
Ecology--Study and teaching--Baltic States--History.
Ecology--Study and teaching--Germany--History.
Ecology--Study and teaching--Switzerland--History.
Germany--Relations--Baltic States.
Germany--Relations--Switzerland.
Switzerland--Relations--Baltic States.
Switzerland--Relations--Germany.