Columbia subject headings:
Genocide--Sudan--Darfur.
Humanitarian assistance--Sudan--Darfur--International cooperation.
Political prisoners--Vietnam.
Slave trade--America--Centennial celebrations, etc.
Harvard subject headings:
Genocide--Sudan--Darfur
Humanitarian assistance--Sudan--Darfur--International cooperation.
Political prisoners--Vietnam
Slave trade--America--Centennial celebrations, etc.
Princeton subject headings:
Genocide--Sudan--Darfur.
Humanitarian assistance--Sudan--Darfur--International cooperation.
Political prisoners--Vietnam.
Slave trade--America--Centennial celebrations, etc.