Columbia subject headings:
Harvard subject headings:
Merchant marine--Europe--History.
Merchant mariners--Europe--History.
Merchant mariners--Supply and demand--Europe.
Sailors--Europe--History.
Shipping--Economic aspects--Europe--History.
Princeton subject headings:
Merchant marine--Europe--History.
Merchant mariners--Europe--History.
Merchant mariners--Supply and demand--Europe.
Sailors--Europe--History.
Shipping--Economic aspects--Europe--History.