Columbia subject headings:
Harvard subject headings:
Diseases--Tropics--Seasonal variations--Congresses.
Rural poor--Tropics--Congresses.
Seasonal variations (Economics)--Tropics--Congresses.
Sociology, Rural.
Princeton subject headings:
Diseases--Seasonal variations--Tropics--Congresses.
Rural poor--Tropics--Congresses.
Seasonal variations (Economics)--Tropics--Congresses.