Columbia subject headings:
Europe, Northern--Discovery and exploration--Greek.
Ocean travel.
Pytheas, of Massalia--Travel--Europe, Northern.
Harvard subject headings:
Europe, Northern--Discovery and exploration--Greek.
Ocean travel.
Pytheas, of Massalia--Journeys--Europe, Northern.
Princeton subject headings:
Europe, Northern--Discovery and exploration--Greek.
Ocean travel.
Pytheas, of Massalia--Travel--Europe, Northern.