Columbia subject headings:
Agriculture--Oregon--Willamette River Valley.
Agriculture.
School farms.
Urban agriculture--Oregon--Willamette River Valley.
Urban agriculture.
Harvard subject headings:
Agriculture--Oregon--Willamette River Valley.
Agriculture--Oregon--Willamette Valley.
Agriculture.
School farms.
Urban agriculture--Oregon--Willamette River Valley.
Urban agriculture--Oregon--Willamette Valley.
Urban agriculture.
Princeton subject headings: