REMOVE

1. railroads
2. soil
3. rubbish
4. pipes (smoking equipment)
5. trees
6. boys

WHAT

1. Visual Works (hierarchy n … (1)
2. armchairs (1)
3. artists (visual artists) (1)
4. beards (1)
5. black-and-white film (1)

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WHO

1. Campbell, Sandra L. Still (1)
2. Sandra L. Still Campbell; … (1)

WHEN

1. 1969 (1)