REMOVE

1. plants
2. trees
3. soil
4. sky
5. tipis
6. rubbish
7. 1937

WHAT

1. Visual Works (hierarchy n … (1)
2. barns (1)
3. barriers (1)
4. black-and-white film (1)
5. buildings (structures) (1)

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WHO

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

WHEN

1. 1961 (1)
2. after 1961 (1)