REMOVE

1. sitting
2. sky
3. farms
4. concrete block

WHAT

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

More 

WHO

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

Less

WHEN

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