Columbia subject headings:
Harvard subject headings:
City walls--Italy--Massa Marittima.
Fortification--Italy--Massa Marittima.
Massa Marittima (Italy)--Buildings, structures, etc.
Princeton subject headings:
City walls--Italy--Massa Marittima.
Fortification--Italy--Massa Marittima.
Massa Marittima (Italy)--Buildings, structures, etc.