Columbia subject headings:
Harvard subject headings:
Agriculture--Economic aspects--China--Ningxia Huizu Zizhiqu.
Environmental protection--China--Ningxia Huizu Zizhiqu.
Green Revolution--China--Ningxia Huizu Zizhiqu.
Princeton subject headings:
Ecology--Economic aspects--Ningxia Huizu Zizhiqu.
Mountains--Economic aspects--China--Ningxia Huizu Zizhiqu.