Yaman, its early mediaeval history - ʿUmārah ibn ʿAlī al-Ḥakamī 1120 or 1121-1174; Ibn Khaldūn, 1332-1406; Janadī, Muḥammad ibn Yaʿqūb -1332?; Kay, Henry Cassels, 1827-1903 (Gregg Internat., 1968)