Columbia subject headings:
Harvard subject headings:
Ecological carrying capacity--China--Beijing.
Ecological carrying capacity--China--Hebei Sheng.
Ecological carrying capacity--China--Tianjin.
Population density--China--Beijing.
Population density--China--Hebei Sheng.
Population density--China--Tianjin.
Princeton subject headings:
Ecological carrying capacity--China--Beijing.
Ecological carrying capacity--China--Hebei Sheng.
Ecological carrying capacity--China--Tianjin.
Population density--China--Beijing.
Population density--China--Hebei Sheng.
Population density--China--Tianjin.