Columbia subject headings:
Canals--Syria--Aleppo--History.
Syria--Antiquities.
Water-supply--Syria--Aleppo.
Harvard subject headings:
Canals--Syria--Aleppo--History.
Syria--Antiquities.
Water-supply--Syria--Aleppo.
Princeton subject headings:
Canals--Syria--Aleppo--History.
Syria--Antiquities.
Water-supply--Syria--Aleppo.