Columbia subject headings:
Animals in literature.
Ethics in literature.
Ethics, Ancient.
Virgil--Ethics.
Virgil--Knowledge and learning.
Zoology.
Harvard subject headings:
Animals in literature
Ethics in literature.
Ethics, Ancient.
Virgil--Ethics.
Virgil--Knowledge--Zoology.
Princeton subject headings:
Animals in literature.
Ethics in literature.
Ethics, Ancient.
Virgil--Knowledge--Zoology.
Virgil--Religion and ethics.