Columbia subject headings:
Art brut.
Art, Amateur.
Outdoor sculpture.
Sculpture, Modern--20th century.
Sculpture, Modern--21st century.
Harvard subject headings:
Art brut.
Art, Amateur.
Art, Modern--20th century
Art, Modern--21st century
Outdoor sculpture.
Princeton subject headings:
Art brut.
Art, Amateur.
Outdoor sculpture.
Sculpture, Modern--20th century.
Sculpture, Modern--21st century.