Columbia subject headings:
Drawing, Italian--Conservation and restoration--Congresses.
Drawing, Renaissance--Conservation and restoration--Congresses.
Leonardo, da Vinci, 1452-1519--Congresses.
Harvard subject headings:
Drawing, Italian--Conservation and restoration--Congresses.
Drawing, Renaissance--Conservation and restoration--Congresses.
Leonardo, da Vinci, 1452-1519--Congresses.
Princeton subject headings:
Drawing, Italian--Conservation and restoration--Congresses.
Drawing, Renaissance--Conservation and restoration--Congresses.
Leonardo, da Vinci, 1452-1519--Congresses.