Columbia subject headings:
Greece.
Italy.
Mediterranean Region.
Twins--Folklore.
Twins--Greek World--History.
Twins--Roman World--History.
Harvard subject headings:
Civilization, Greco-Roman.
Twins in literature.
Twins--Greece.
Twins--Mythology
Twins--Rome.
Princeton subject headings:
Civilization, Greco-Roman.
Twins in literature.
Twins--Greece.
Twins--Mythology.
Twins--Rome.