Columbia subject headings:
Artists' preparatory studies--Italy, Northern.
Drawing, Renaissance--Italy, Northern--Catalogs.
Drawing, Renaissance--Italy, Northern.
Harvard subject headings:
Drawing, Italian--Italy--Po River Valley.
Drawing, Renaissance--Italy--Po River Valley.
Princeton subject headings:
Artists' preparatory studies--Italy.
Drawing, Italian--Italy, Northern--15th century.
Drawing, Italian--Italy, Northern--16th century.
Drawing, Renaissance--Italy, Northern.