REMOVE

1. soil
2. Yaddo
3. plants
4. horizon line
5. 1949

WHAT

1. Visual Works (hierarchy n … (1)
2. arbors (1)
3. artists (visual artists) (1)
4. atmospheric perspective (1)
5. automobiles (1)

More 

WHERE

1. Westminster, Maryland (1)

WHO

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

WHEN

1. 1961 (1)
2. 1965 (1)
3. between 1961 - 1965 (1)