Munk, , pp. 94 et seq.; Dozy, R. , German ed., ii. 300 et seq.; Grätz, vi. 55 et seq., 415 et seq.; Ersch & Gruber, section ii., part 31, p. 86.; Medieval Sourcebook: Abraham Ibn Daud: On Samuel Ha-Nagid, Vizier of Granada, 11 Cent Nagdela (Nagrela), Abu Husain Joseph Ibn by Richard Gottheil, Meyer Kayserling, . 1906 ed.