Columbia subject headings:
Harvard subject headings:
Hokkaido (Japan)--History.
North Pacific Ocean--History.
Whaling--Japan--Hokkaido--History.
Whaling--North Pacific Ocean--History.
Princeton subject headings:
Hokkaido (Japan)--History.
North Pacific Ocean--History.
Whaling--Japan--Hokkaido--History.
Whaling--North Pacific Ocean--History.