Columbia subject headings:
Irrigation engineering--Yemen (Republic)--Ṣanʻāʼ.
Water-supply engineering--Yemen (Republic)--Ṣanʻāʼ.
Waterworks--Yemen (Republic)--Ṣanʻāʼ.
Harvard subject headings:
Irrigation engineering--Yemen (Republic)--Ṣanʻāʼ.
Water-supply engineering--Yemen (Republic)--Ṣanʻāʼ.
Waterworks--Yemen (Republic)--Ṣanʻāʼ.
Princeton subject headings:
Irrigation engineering--Yemen--Ṣanʻāʼ.
Water-supply engineering--Yemen--Ṣanʻāʼ.
Waterworks--Yemen--Ṣanʻāʼ.