Columbia subject headings:
Fortification--Finland--Suomenlinna--Designs and plans.
Military architecture--Finland--Suomenlinna.
Suomenlinna (Finland)
Harvard subject headings:
Military architecture--Finland--Suomenlinna.
Suomenlinna (Finland)--History.
Princeton subject headings:
Fortification--Finland--Suomenlinna.
Military architecture--Finland--Suomenlinna--Designs and plans.
Suomenlinna (Finland)