Columbia subject headings:
Egypt--Description and travel.
Nile River.
Sudan--Description and travel.
Harvard subject headings:
Egypt--Description and travel.
Nile River--Description and travel.
Nile River--Discovery and exploration.
Nile River.
Slave trade--Africa
Southworth, Alvan S.--Travel--Africa.
Sudan--Description and travel.
Princeton subject headings:
Egypt--Description and travel.
Nile River.
Sudan--Description and travel.