Columbia subject headings:
Groningen (Netherlands)--Buildings, structures, etc.
Martinikerk (Groningen, Netherlands)
Towers--Netherlands--Groningen.
Harvard subject headings:
Princeton subject headings:
Bell towers--Conservation and restoration--Netherlands--Groningen.
Bell towers--Netherlands--Groningen.
Groningen (Netherlands)--Buildings, structures, etc.
Martinikerk (Groningen, Netherlands)