Columbia subject headings:
Duomo di Milano.
Marble industry and trade--Italy--Candoglia.
Marble industry and trade--Italy--Ornavasso.
Quarries and quarrying--Italy--Candoglia.
Quarries and quarrying--Italy--Ornavasso.
Harvard subject headings:
Duomo di Milano.
Marble industry and trade--Italy--Verbano Cusio Ossola--History.
Quarries and quarrying--Italy--Verbano Cusio Ossola--History.
Princeton subject headings:
Duomo di Milano.
Marble industry and trade--Italy--Candoglia.
Marble industry and trade--Italy--Ornavasso.
Quarries and quarrying--Italy--Candoglia.
Quarries and quarrying--Italy--Ornavasso.